289CHAPTER 9

Maternal–Child Nursing: Pediatrics

Tonya A. Schneidereith

The physical manifestations of genetic disorders are frequently identified first in infants and children, presenting as either obvious external malformations or more occultly as inborn errors of metabolism. Regardless of the type of genetic disorder diagnosed in a child, certain reactions often occur. A number of factors influence these reactions, including whether the disorder is visible, such as Down syndrome (DS), or hidden, such as congenital heart disease (CHD). Alterations in pediatric gene function frequently lead to chronic illness, affecting not only the child and parents, but siblings, grandparents, and extended family members. The ways in which the family is informed of the disorder, the supports provided, referrals made, and familial strengths influence short- and long-term coping. Genetic counseling is important for these families, including options relating to treatment, prenatal diagnosis, and reproductive options. Additional considerations for the family include anticipatory guidance, short- and long-term plans, coping with associated symptoms and conditions, insurance issues, resources, and school or work issues.

This chapter identifies the most common birth defects, chromosome disorders, and single gene disorders recognized in infancy and childhood.

BIRTH DEFECTS

The terms birth defects and congenital anomalies are essentially synonymous. Both are meant to convey a defect that is present at the time of delivery. Although sometimes obvious, the visual appearance does not always identify the etiology. For example, a cleft palate may be an isolated anomaly or part of a syndrome. It may be caused by a chromosomal aberration, a single gene disorder, an environmental insult, a combination of genetic and environmental factors, or unknown causes. Prenatal development is extremely complex, involving cell proliferation, differentiation, migration, programmed cell death, fusion between adjacent tissues, and effective chemical communication. The correct sequence and timing are crucial. Birth defects may be caused by any of the factors in Box 9.1.

According to the Centers for Disease Control and Prevention, approximately 3% of babies born in the United States have a birth defect. Although there are a plethora of birth defects, this section expands on those believed to be of multifactorial causation.

Terminology

The nomenclature associated with birth defects varies. Terms like malformations, anomalads, and complexes have not been used with consistent meaning in the literature. Examples of definitions of the ones most likely encountered by the nurse are shown in Box 9.2. Other terms that describe various anomalies, such as agenesis, aplasia, dysplasia, and hyperplasia, are defined in the glossary at the end of this book.

Multifactorial Causation and Inheritance

The common congenital anomalies often have a familial basis, but they usually do not fit a Mendelian inheritance pattern or show an association with a chromosomal abnormality. Although exact causes remain unknown for the most part, it is believed that many of the common congenital malformations and isolated birth defects are inherited in a multifactorial manner, involving the interaction of several genes and the environment (see Table 9.1). The reasons for these are under investigation, including chromosomal deletions and duplications. An example is DiGeorge or velocardiofacial syndrome (VCFS), where microdeletions of chromosome 22q11.2 are associated with hypoplasia of the parathyroid gland, the thymus, and the cardiac outflow tracts. Even if a person had chromosomal or other testing that was negative years ago, it may be useful to repeat such testing in order to provide updated genetic counseling information.

Congenital Heart Disease

Approximately 35,000 babies are born in the United States each year with CHD. The defects can vary from simple to complex and may require extensive surgical repair. The etiology varies, with about 5% to 10% originating from chromosome or single gene mutation and 1% to 2% being of environmental origin. CHD may be due to:

Source: www.cdc.gov

Children with CHD frequently have one or more extracardiac defects, ranging from 25% to 45%. Thus, all children known to have CHD should be carefully evaluated in order to detect other such anomalies. Some anomalies, such as cleft palate, are readily apparent, but others, such as those of the urinary tract, are more difficult to detect. The most frequent extracardiac defects associated with CHD are of the genitourinary tract, gastrointestinal tract, and musculoskeletal system. Nonimmune fetal hydrops (generalized edema and ascites in the fetus) is estimated to have a cardiac cause in as many as 25% of the cases. The most frequent congenital heart defects found in association with other anomalies include patent ductus arteriosus, atrial septal defects, atrioventricular septal defect, tetralogy of Fallot, coarctation of the aorta, ventricular septal defects, and malposition defects. About 10% of all CHDs are part of a syndrome (e.g., coarctation of the aorta and Turner syndrome). It is important to recognize these syndromes in order to provide accurate genetic counseling and management. Recurrence risk figures vary for the type of defect, as well as for other factors previously discussed. If the CHD is multifactorial, an overall risk to 293a future sibling of an affected individual is 2% to 4%. This increases to 6% to 12% if a second sibling is affected.

An exciting advancement in CHD includes work by the Pediatric Cardiac Genomics Consortium. Sponsored by the National Heart, Lung, and Blood Institute (NHLBI), this translational research group is collecting data from multiple sites on the genetic causes of CHD. Through their “Bench to Bassinet” program, scientists are correlating data obtained from animal models with specific pediatric cardiac anomalies. To date, significant de novo mutations in genes involved in histone methylation have been identified, while the size of the estimated gene set involved in CHD is 401 genes.

Because of effective early interventions, many persons with CHD survive into adulthood. There are clinicians who specialize in adult CHD, and many may seek medical care accompanied by their parents into their 30s. A resource devoted to CHD can be found online (www.pted.org).

Developmental Dysplasia of the Hip (DDH)

Developmental dysplasia of the hip (DDH) is the most common orthopedic disorder in newborns. The interaction of genetic and environmental factors in DDH is striking. It is now thought of by most as a deformation rather than a true congenital malformation, with an incidence of about 1% of all live births, depending on the criteria used and the age of assessment. A full range of severity is possible, from a lax dislocatable hip to a dislocated hip that cannot be reduced. DDH is more common in firstborn children, in breech presentations, those with a positive family history, and is six times more common in females. Environmental factors present after birth may contribute to the development of DDH, including the use of a cradle board and swaddling. In Japan, the incidence of DDH decreased from 3.5% to 1.5% following a national effort to eliminate swaddling infants. Additional risk factors include the nature of the hip joint (e.g., a shallow-angled acetabulum is more susceptible to dislocation) or lax connective tissue from either heritable causes or hormones (e.g., inborn errors of estrogen or collagen metabolism, maternal estrogens, or hormones that may be given before delivery). Recently growth factor genes have been identified as susceptible to DDH, some of which include GDF5, TBX4, ASPN, IL-6, TGF-β 1, and PAPPA2.

The nurse should carefully assess neonates and infants for clinical features of DDH by examining for shortening of the thigh with bunching up of tissue and skin fold accentuation, limitation of abduction, or other signs. The Ortolani or Barlow test may also be done. However, DDH may not be detected at birth, and surveillance should be maintained (Box 9.3). Ultrasound screening of the neonatal hip has become more common and has a specificity and sensitivity of over 90%. DDH is relatively easy to treat if diagnosed early, but if it is discovered after 1 year of age, more complex management is required and complete correction may not be possible. Nurses should be especially alert examining infants who are female, firstborn, and delivered in a breech position. Health teaching should include information about optimum positioning.

Neural Tube Defects

Neural tube defects (NTDs) are congenital anomalies that affect the embryonic neural tube, the structure that ultimately develops into the brain and spinal cord. Many of these aberrations occur to the embryo during the first month of pregnancy, prior to a woman knowing that she is pregnant. The most common forms of NTDs include anencephaly, encephalocele, and spina bifida. Spina bifida can be further classified as spina bifida occulta, meningocele, or myelomeningocele, defined in Box 9.4.

A large proportion of NTDs can be detected prenatally by ultrasound and through measurement of α-fetoprotein (AFP) in maternal serum and amniotic fluid. Neural tube defects can be open or closed. In open NTDs, neural tissue is either exposed or covered with a thin transparent membrane. In closed NTDs, neural tissue is covered with skin or a thick, opaque membrane and therefore may not be detected by α-fetoprotein levels. Hydrocephalus may accompany spina bifida. Anencephaly and spina bifida are related etiologically and are generally discussed together. After having an infant with either anencephaly or spina bifida, the recurrence risk is for either one, not just for the anomaly that was present in the affected infant.

295A consistent observation has been that NTDs are more frequent in poorer socioeconomic groups and in conditions that result in poor diets, especially folic acid deficiency, but may also include deficiency in ascorbic acid and zinc. Although periconceptional intake of folic acid has decreased the frequency of NTDs, some studies have found a higher risk of NTDs in obese women that is independent of folic acid intake. Hyperthermia, such as that with sauna or hot tub use or maternal illness with fever, during early pregnancy has been shown to be capable of causing NTDs, especially anencephaly.

The vast majority of NTDs are attributable to genetic factors, including associations with folate-related genes and planar cell polarity genes. The MTHFR gene, located on the short arm of chromosome 1, is a folate-related gene that has shown a positive association with NTDs. A mutation in this gene leads to a form of methylenetetrahydrofolate reductase that is not as active at higher temperatures, possibly explaining why there is a relationship between NTDs and hyperthermia.

Surgical repair of NTDs can include the placement of a shunt, with the extent of surgery dependent on the severity of the defect. Long-term rehabilitation may be necessary, often requiring bowel and bladder training. In some centers, fetal surgery is performed to close myelomeningoceles, decrease shunting, and improve motor function.

In anencephaly, the infant’s appearance is so shocking that often parents equate the severity of disease with the risk of recurrence. In fact, it falls into the same general range of other multifactorial disorders. Recurrence risks must always be adjusted to the population incidence, ethnic background, the number of affected relatives, and epidemiological factors when known. In general, however, the risk of recurrence in the United States for a Caucasian couple after having one affected infant and no other affected relatives is believed to be 3% to 4%. The risk for a woman with spina bifida to have an affected child is about 4%. There is some indication that there is an increased risk for NTDs among siblings of children who have other birth defects, such as cleft lip and palate.

The most important aspect of NTDs is prevention. It was discovered first that recurrence of NTDs could be prevented by periconceptional supplementation of folic acid and vitamins, followed by the expansion of this to prevent first occurrences as well. Recommendations are 0.4 mg (400 μg) of folic acid for all women of childbearing age. The American College of Medical Genetics also recommends that women with a previous history of NTDs take 4.0 mg of folic acid daily, optimally starting 3 months before conception.

Poor maternal nutrition in general may also contribute to NTD occurrence, as well as other birth defects including imperforate anus. Dietary counseling that is ongoing and periodically reinforced should be provided to females when reproductive age is reached.

Orofacial Clefts

The most common oral clefts are cleft lip, with or without cleft palate (CLP), and cleft palate alone (CP). Over 300 syndromes that include CLP or CP have been recognized. 296Cleft uvula (1:80) and submucous cleft palates (1:1,000) are thought to represent incomplete forms of cleft palate.

Approximately 30% of orofacial clefts are accompanied by other congenital anomalies, including CHD, CHARGE syndrome, ectodermal dysplasia, and multiple forms of cancer. It is important that the infant with a cleft be fully evaluated to exclude other chromosomal disorders and single gene defects. Many genes related to syndromes associated with cleft lip and palate have been identified, while cleft lip and palate alone may be associated with noncoding, regulatory regions. More recently, studies investigating copy number variations (CNVs) suggest that the cumulative effect of changing the copy number of genes through duplications or deletions may result in abnormal phenotypes.

Environmental factors also appear to have a role. Preconceptional multivitamins including B₁₂ and folic acid supplementation have been reported to reduce the recurrence risk of orofacial clefts by as much as 50%. Cigarette smoking during pregnancy also appears to be a risk factor.

The appearance of a child with a cleft is shocking to the parent who is expecting a normal baby. They experience the same reactions most other parents experience for other birth defects, including guilt, anger, denial, and concern. Parents have also stated that an orofacial cleft was not an anomaly that could be hidden from others. Great sensitivity and skill are needed on the part of the entire professional staff immediately after the birth of the infant and throughout the hospital stay. Before leaving the hospital, contact should be arranged for the parents with the cleft palate team (who will ultimately be involved in the lengthy treatment) and also with one of the cleft palate parent groups for support and in-hospital visitation. Referral may be made to the local home health care or community health agency for a home visit by a nurse.

An immediate challenge is that of feeding the newborn with a cleft. It is important for the nursing staff to spend time helping the mother to feel comfortable feeding her infant because she will soon be assuming this responsibility alone. Infants with CLP or CP often cannot create adequate suction and may need a small plastic artificial palate or a different type of nipple. Breastfeeding may be possible, depending on the nature of the cleft. There are publications available to help the nurse advise the mother who wishes to do this, and mothers should not be discouraged. Infants should be held upright when fed to prevent choking and may need to be burped frequently, as they tend to swallow air. The infant may need 30 to 45 minutes or more to feed. Parents need to feel comfortable, the child needs nourishment, and both need to develop an emotional bond to one another. Many parent groups have individuals who come to the home with various successful “tricks” for feeding. The American Cleft Palate Educational Foundation can supply addresses of the local chapter.

It is not uncommon for genetic counseling to be sought by an adult with CLP or CP. The risk for an affected parent and one sibling is about 1 in 10. Often such adults have experienced emotional trauma in their own life, which they attribute to the anomaly, and they may require more in-depth counseling. Three-dimensional ultrasonography of the fetal face may help in prenatal detection.

The total habilitation of infants with oral clefts is complex, often requiring multiple surgical procedures and other therapies, and is generally agreed to be best 297accomplished by a team. The early involvement of the family with such a team provides ongoing family support as well as other optimal therapy. Team members usually consist of professionals with specialties in pediatrics, plastic surgery, audiology, speech pathology, nursing, genetics, dentistry, orthodontia, otolaryngology, social service, and general surgery. Other specialists may include psychologists, nutritionists, and radiologists. Comprehensive, coordinated, and integrated multidisciplinary services are essential.

The current trend is to repair cleft lips as early as possible, almost always before 3 months of age. Many surgeons allow an infant to resume nursing 24 hours after cleft repair. Mothers can manually express breast milk for feeding during periods when the infant cannot nurse. A variety of procedures are used for CP closure, depending on the exact nature of the cleft and its extent.

During infancy and childhood, children with CLP have increased susceptibility to ear infections and frequently having hearing problems. Routine ear exams and testing should be done periodically and their importance explained to the parents. Hearing loss can also be responsible for speech distortion, and hypernasality is a frequent finding. There is a tendency for children with a cleft to develop speech later than usual, and therefore may need some language stimulation, which parents can provide in consultation with the speech pathologist. Parents should be told that hearing problems and discomfort may cause increased fussiness. Additionally, counseling assistance for the client and family may be beneficial due to the psychological sequelae and problems from the hearing and speech problems.

CHROMOSOME DISORDERS

Information about the structure and variation in chromosomes has been described in Chapters 2 and 4. Many fetuses with severe chromosomal abnormalities die prenatally or relatively soon after delivery, especially if the chromosomal defect is nonmosaic. Thus, only three trisomies (13, 18, and 21) are relatively common among live-born infants. Other trisomies and the monosomies are almost always mosaics, which include a normal cell line, with the assumption that enough normal cells are present to be compatible with life. A variety of structural changes of every chromosome have been reported, although each change is extremely rare. The only autosomal deletion defects that are relatively common (1:20,000 to 1:50,000) are cri-du-chat (5p^–), DiGeorge/velocardiofacial syndrome (22q11.2^–), and Wolf–Hirschhorn syndrome (4p16.3^–).

The major autosomal abnormalities are:

298Among the sex chromosome disorders, the overall incidence is about 1 in 300 live births. The most common are:

In any of the trisomies, especially DS, the actual error can be caused by either the presence of an extra free chromosome or one that is translocated to another chromosome. In translocations, the chromosomal material of 47 chromosomes and three copies of those genes are present instead of the normal two copies, but the chromosome count is 46. This illustrates one reason that a full chromosome analysis is necessary.

The risks for recurrence are very different for translocations than free trisomies. For example, in DS, if one parent has 45 chromosomes and a translocation of chromosome 21 to chromosome 14, the gametes they produce can theoretically result in six possible combinations in a zygote, shown in Figure 9.1. In theory, the chance of each occurring is equal, and because three of the six outcomes result in nonviable offspring, the chances of a normal child, a balanced translocation carrier like the parent, or one with DS would each be one third. In practice, the distribution is observed to be different. If the female is the translocation carrier, then the actual observed risk is 10% to 15% for having a child with DS, whereas if the male is the carrier, it is 5% to 8%. The risk for having a normal-appearing child who, like the parent, is a translocation carrier is about 45% to 50%. In either case, the option of prenatal diagnosis should be explained to the parents. If both chromosomes 21 are involved in the translocation, 45,XX,t(21;21) or 45,XY,t(21;21), then only DS offspring can result since the monosomic alternative is nonviable. Therefore, the risk for parents with this type to have a child with DS is 100%. These parents should have genetic counseling that includes discussion of other reproductive options. Although more children with translocation DS are born to women under 30 years of age than over 30 years of age, assumptions of cause can never be made. Chromosome analysis must be done. The degree of mosaicism, if present, can also act to modify findings and prognosis. See Figure 9.2 for a karyotype illustrating the major autosomal and sex chromosome abnormalities.

Other than DS, those affected with severe autosomal anomalies die relatively soon after delivery or in the first year of life because multiple, severe, life-threatening problems are present. Some, particularly those who are less severely affected or are mosaic, do survive. Parents often have angry feelings toward professionals who may have told them that their child would not live beyond a certain age. Therefore, it is important to provide accurate information in a sensitive manner. One parent organization specifically for rare chromosome disorders is the Support Organization for Trisomy 18, 13 and Related Disorders (www.trisomy.org). DS is described in the following text. Information about the other autosomal chromosomal disorders is given in Table 9.2.

299

FIGURE 9.1. Possible reproductive outcomes of a 14/21 balanced translocation carrier.

300

FIGURE 9.2. G-banded karyotype illustrating major chromosome aberrations in a composite.

Trisomy 21 (Down Syndrome)

Described by Dr. John Langdon Down in 1866, DS occurs in approximately 1 in 830 newborns. In 1959, Dr. Jerome Lejeune identified an extra chromosome 21 in three males with features associated with DS. This was the first chromosome abnormality associated with a specific chromosome.

There is no way, other than chromosome analysis, to tell if a free trisomy (about 95%), a translocation (about 5%), or mosaicism is present. About 90% of the time, the extra chromosome is of maternal origin. The area responsible for the phenotypic traits of DS has been identified as the Down syndrome critical region (DSCR), located on the long arm of Chromosome 21 at q22.1~21q22.3. Therefore, a complete trisomy is not necessary for typical clinical features (Figure 9.3) which can include:

Source: National Library of Medicine (2015)

302

FIGURE 9.3. Typical phenotype of child with Down syndrome.

Source: Weijerman & de Winter, 2010

303The karyotype of a patient with a trisomy 21 is shown in Figure 9.4. Whether due to a complete trisomy, translocation, or mosaicism, the severity of the disorder and the degree of developmental delay are not always as evident in the infant, making it hard for many parents to accept the diagnosis. It takes time to fully realize the impact of the diagnosis and for realistic decision making to occur. Support is essential, and it should be suggested to the parents that they enroll their baby in an early intervention program as part of the effort to maximize their child’s potential. Many persons with DS function at a higher social level than intellectual level.

Persons with DS require standard childhood care such as immunizations and growth monitoring with appropriate standards. However, the eyes and ears require special attention for problems such as strabismus, myopia, otitis media, and hearing loss. In addition, monitoring for heart disease, hematologic problems, orthopedic problems, gastrointestinal disorders, and abnormal thyroid function should also be part of standard care. Many individuals with DS are uniformly happy, friendly, and have good dispositions. However, others can be stubborn, mischievous, and poorly coordinated, and about 10% have serious emotional problems.

Males usually have hypogonadism and are infertile, whereas females can be fertile. Those with free trisomy have a 50% risk of having offspring with DS. At one time, involuntary sterilization of people with DS was almost routinely carried out in many institutions and is still part of the law in some states, although rarely invoked. It is important to provide developmentally appropriate sex education, including socially acceptable sexual behavior. Many parents need help recognizing the sexuality of their adolescent or young adult. Appropriate contraceptive information and care should also be provided. Adults with DS require care from clinicians who understand the syndrome and its manifestations and can provide sensitive, coordinated care.

FIGURE 9.4. Trisomy 21 karyotype.

Source: Down Syndrome Karyotype, 2006.

304With a current life expectancy of 60 years of age, health maintenance visits should include planning and discussion on transitioning to adulthood, appropriate school placements, vocational training, and health promotional programs for weight control. Additional considerations include education regarding increased possibilities of premature aging and development of early Alzheimer disease.

Families will require ongoing psychological support and counseling. Those with DS require ongoing medical treatment and, often, surgical procedures that may be difficult for both the affected person and the family. Detailed guidelines for health management have been developed by the American Academy of Pediatrics. Additionally, resources for families can be found on the National Down Syndrome Society website (www.ndss.org).

The Sex Chromosomes and Their Abnormalities

The human sex chromosomes are the X and the Y chromosome. Normal human females are 46,XX, and normal human males are 46,XY. Chromosome X contains over 1,400 genes, while chromosome Y contains over 200 genes (www.ncbi.nlm.nih.gov/books/NBK22266/#A295). As described in Chapter 4, daughters normally receive one X chromosome from the father and one from the mother. Sons normally receive an X chromosome from the mother and the Y chromosome from the father. In females, as discussed in Chapter 4, one of the two X chromosomes is inactivated within somatic cells, although a few genes apparently escape X inactivation.

Although nondisjunction gives rise to most of the sex chromosome abnormalities, neither 45,X nor 47,XYY is associated with increased parental age. The possible reproductive outcomes arising from meiotic nondisjunction at oogenesis and spermatogenesis are illustrated in Figure 9.5. First-division nondisjunction does not result in a normal karyotype, whereas second-division nondisjunction results in half-normal and half-abnormal gametes and offspring.

Considering all the sex chromosome aneuploidies together, the overall incidence is about 1 in 400 newborns. The most common sex chromosome variations are those in which there is an extra or missing X or Y chromosome, resulting in Turner syndrome (45,X), triple X (47,XXX), Klinefelter syndrome (47,XXY), or XYY (47,XYY). Those in which more X or Y chromosomes are added, such as tetrasomy or pentasomy X (48,XXXX; 49,XXXXX), are rare, and intellectual disability is common. For sex chromosome variations, the most common mosaic conditions are 46,XX/47,XXY; 45,X/46,XX; 46XX/47,XXX; and 46,XY/47,XYY.

In general, those with mosaic sex chromosome abnormalities tend to show milder signs, and the degree tends to be related to the percentage of abnormal cells. The identification of persons with sex chromosome abnormalities often occurs at the following points in the life cycle (examples are given in parentheses):

305

FIGURE 9.5. Possible reproductive outcomes after meiotic nondisjunction of sex chromosomes.

Mildly affected individuals, especially some with 47,XYY, 47,XXY, and 47,XXX or mosaics, may go unrecognized. Sex chromosome variations appear more frequently after the use of intracytoplasmic sperm injection, a method of assisted reproductive technology.

The four major sex chromosome variations (45,X; 47,XXX; 47,XXY; 47,XYY) are summarized in Table 9.3, and Turner and Klinefelter syndromes are discussed in the following text. The major sex chromosome disorders or variations are illustrated by karyotype in Table 9.3.

Turner Syndrome (45,X)

This monosomy is usually written as 45,X. The complete absence of the X chromosome occurs in about 50% to 60%, with the rest having various combinations of partial deletion, isochromosome formation, and 45,X/46,XX mosaicism. In about 75% of the cases, individuals with Turner syndrome have the maternal X chromosome, while 25% have the paternal X chromosome, and there may be a relationship between decreased maternal age and a missing maternal X chromosome. Something under maternal control (e.g., rates of aneuploidy) may have a larger role once attributed to paternal loss of the chromosome.

Chromosome analysis is necessary not only for diagnostic confirmation but also because about 25% of mosaic individuals can menstruate. There is also an increased risk of malignancies such as dysgerminomas or gonadoblastomas in those with a XY cell line (5%–6%).

Phenotypically, short stature is the most consistent feature, with an average untreated height attainment of about 144 cm (4ʹ6ʺ). Final height in those with 307Turner syndrome is influenced by other height-determining factors such as parental height and the extent of ovarian failure and cardiovascular status.

Prenatal detection is possible through chromosome analysis or sometimes through characteristics revealed on ultrasonography. Other cases are detected in later childhood because of the child’s short stature, the lack of secondary sex characteristics at puberty, or the absence of menarche (about 90%). Some are not detected until adulthood, when they are noted to have amenorrhea or infertility. The external genitalia and vagina remain infantile without hormone therapy.

Common clinical features include:

308If untreated, the greatest problems reported by patients are short stature and the absence of secondary sex characteristics. Early diagnosis before cessation of bone growth permits the use of recombinant growth hormone (GH) therapy, often with oxandrolone, usually beginning at about age 9 or 10 years. This may be followed by ethinyl estradiol with or without progesterone to induce breast development, menstruation, and vaginal maturation. Growth velocity should be monitored with specific growth charts for Turner syndrome. It should be stressed that females with Turner syndrome have a feminine gender identity, so if reproduction is desired, referral should be made to specialists in this area. Family support groups and information are available through the Turner Syndrome Society of the United States (www.turnersyndrome.org).

Klinefelter Syndrome (47,XXY)

In Klinefelter syndrome (47,XXY), the origin of the extra X chromosome is maternal in about 50% of cases and paternal in 50% of cases. Klinefelter syndrome is underdiagnosed as most of the affected males are not identified until the absence of secondary sex characteristics is noted. These individuals may exhibit sparse body hair, gynecomastia, or small testes on physical exam. In adults, 47,XXY men may account for 14% of the cases of azoospermia; many are first diagnosed with evaluation for infertility. Some reports indicate an increase in the presence of minor congenital anomalies, especially clinodactyly. If multiple anomalies are present, these boys might be detected through chromosome analysis in infancy.

Penile size may be small (below the 50th percentile) in children, but is usually near normal in adolescence and adulthood alongside normal sexual functioning. Development of gynecomastia is more common and tends to persist in males with Klinefelter syndrome. An increased risk of breast cancer and various germ cell tumors has been noted in these individuals. Mammoplasty or prophylactic mastectomy may be recommended for patients with persistent gynecomastia.

Clinical features include:

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