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Pediatric Endocrinology, New York Presbyterian Hospital-Weill Cornell Medical Center, New York, New York 10021
Address all correspondence and requests for reprints to: Maria I. New, M.D., Department of Pediatrics, Division of Pediatric Endocrinology, New York Hospital-Cornell Medical Center, 525 East 68th Street, Room M-622, New York, New York 10021.
Abstract
Congenital adrenal hyperplasia (CAH) refers to a family of monogenic inherited disorders of adrenal steroidogenesis most often caused by enzyme 21-hydroxylase deficiency (21-OHD). In the classic forms of CAH (simple virilizing and salt wasting), androgen excess causes external genital ambiguity in newborn females and progressive postnatal virilization in males and females. Prenatal treatment of CAH with dexamethasone has been successfully used for over a decade.
This article serves as an update on 532 pregnancies prenatally diagnosed using amniocentesis or chorionic villus sampling between 1978 and 2001 at New York Presbyterian Hospital-Weill Medical College of Cornell University. Of the 532 pregnancies, 281 were prenatally treated for CAH due to the risk of 21-hydroxylase deficiency. Follow-up telephone interviews with mothers, genetic counselors, endocrinologists, pediatricians, and obstetricians were performed in all cases.
Of the pregnancies evaluated, 116 babies were affected with classic 21-OHD. Of these, 61 were female, 49 of whom were treated prenatally with dexamethasone. Dexamethasone administered at or before 9 wk gestation (in proper doses) was effective in reducing virilization. There were no statistical differences in the symptoms during pregnancy between mothers treated with dexamethasone and those not treated with dexamethasone, except for weight gain, edema, and striae, which were greater in the treated group. No significant or enduring side-effects were noted in the fetuses, indicating that dexamethasone treatment is safe. Prenatally treated newborns did not differ in weight from untreated, unaffected newborns. Based on our experience, prenatal diagnosis and proper prenatal treatment of 21-OHD are effective in significantly reducing or eliminating virilization in the newborn female. This spares the affected female the consequences of genital ambiguity, genital surgery, and possible sex misassignment.
CONGENITAL ADRENAL HYPERPLASIA (CAH) is a
family of inherited disorders of adrenal steroidogenesis
(1). Each disorder results from a deficiency in one of the
five enzymatic steps necessary for normal cortisol synthesis (Fig. 1
). Deficiency of 21-hydroxylase (21-OHD)
accounts for over 90% of CAH cases. There is a wide range of clinical
presentations in classic and nonclassic CAH, from virilization with
labial fusion to precocious adrenarche, pubertal or postpubertal
virilization, and reduced fertility.
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) After
birth, males and females exhibit progressive postnatal virilization,
which may include progressive penile or clitoral enlargement,
precocious pubic hair, hirsutism, acne, advanced somatic and epiphyseal
development, and central precocious puberty. Reduced fertility and
menstrual abnormalities have been observed in women, and testicular
adrenal rests have been found in untreated men (2, 3, 4, 5).
There are two forms of classical steroid 21-OHD, the simple virilizing
and the salt-wasting types. Three-fourths of classical cases are
salt-wasting (1). To some extent, the symptoms can be
arrested or reversed by treatment with glucocorticoid, which suppresses
ACTH stimulation of the adrenal cortex. Those patients with aldosterone
deficiency require treatment with salt-retaining steroids as well.
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Analysis of CAH incidence data from almost 6.5 million newborns screened in the general population worldwide has demonstrated an overall incidence of between 1 in 13,000 and 1 in 15,000 live births for the classic form of CAH (7, 8, 9). The disease frequency of nonclassic CAH in the general heterogeneous population of New York City is 1 in 100, and 1 in 7 is a carrier (10).
Patients with CAH present with a unique hormonal profile due to their enzymatic deficiency. In our experience the best hormonal diagnostic test for 21-OHD has proven to be the ACTH (Cortrosyn, 0.25 mg) stimulation test measuring the serum concentration of 17-hydroxyprogesterone (17-OHP). After administration of an iv bolus of ACTH (preferably in the morning due to the diurnal variation in 17-OHP), 17-OHP is measured at 0 and 60 min. A logarithmic nomogram we developed provides hormonal standards for assignment of the 21-OHD type by relating baseline to ACTH-stimulated serum concentrations of 17-OHP (11).
Molecular genetics
CAH due to 21-OHD is a monogenic autosomal recessive disorder. The gene for adrenal 21-hydroxylase, CYP21, is located about 30 kb from a pseudogene, CYP21P, on chromosome 6p, adjacent to the human leukocyte antigen (HLA) genes. The high degree of sequence similarity (96–98%) between CYP21 and CYP21P permits two types of recombination events: 1) unequal crossing-over during meiosis, which results in complete deletions/duplications of CYP21 and the possible transmission of a null allele, and 2) and gene conversion events that transfer deleterious mutations present in the pseudogene to CYP21 (12, 13, 14). Deletions generally account for 20–25% of classic 21-OHD alleles, and small deletions and point mutations make up the rest.
Specific mutations may be correlated with a given degree of enzymatic compromise and a clinical form of 21-OHD (15, 16, 17, 18, 19). The genotype for the classical form of CAH is predicted to be a severe mutation on both alleles at the 21-OH locus, with markedly decreased enzymatic activity generally associated with salt wasting. The point mutation A (or C) to G near the end of intron 2, which is the single most frequent mutation in classic 21-OHD, causes premature splicing of the intron and a shift in the translational reading frame (12, 16). Most patients who are homozygous for this mutation have the salt-wasting form of the disorder (20, 21). Recent studies, however, have demonstrated that there is occasionally a divergence in phenotypes within mutation-identical groups, the reason for which requires further investigation (21, 22).
Prenatal diagnosis and treatment
When it was discovered that CAH-affected fetuses exhibit
elevated 17-OHP and 
4-androstenedione
concentrations in their amniotic fluid, measuring their levels by
amniocentesis and hormonal assay became the first method of prenatal
diagnosis for this disorder. As amniocentesis is performed in the
second trimester, it is too late start dexamethasone treatment to
prevent virilization of a female fetus. Thus, dexamethasone could be
initiated in a pregnancy at risk before the second trimester, but
17-OHP would be suppressed and cannot be relied upon for diagnosis.
When HLA was found to be linked to CAH, diagnoses were made by using
HLA genetic linkage marker analysis. This method resulted in many
diagnostic errors due to recombination or haplotype sharing. The method
currently used is direct DNA analysis of the 21-OH gene (CYP21) with
molecular genetic techniques (23, 24, 25). Chorionic villus
sampling (CVS) can also be used to obtain fetal tissue for prenatal
diagnosis by molecular genetic analysis at 9–11 wk gestation. However,
this is still too late for prenatal treatment, which must begin before
the 10th week of gestation to prevent virilization.
Prenatal treatment of 21-OHD with dexamethasone has now been used since 1984 (26). Dexamethasone is used because it is not CBG bound in the maternal blood, and the placenta, which has 11ß-hydroxysteroid dehydrogenase enzyme, cannot metabolize dexamethasone the way it metabolizes hydrocortisone. Thus, dexamethasone crosses the placenta from the mother to the fetus and suppresses ACTH secretion.
An algorithm was first published in 1990 for the prenatal diagnosis of
21-OHD CAH using direct molecular analysis of the 21-OH locus and
dexamethasone treatment (27) (Fig. 3). When properly administered,
dexamethasone is effective in preventing ambiguous genitalia in the
affected female, and it has been shown to be safe for both the mother
and the fetus. The largest human studies published to date have shown
no congenital abnormalities that could be attributed with certainty to
dexamethasone (23, 24, 25).
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Since 1978, prenatal examination for CAH due to 21-OHD has been carried out in 624 pregnancies at New York Presbyterian Hospital-Weill Medical College of Cornell University. Prenatal therapy using dexamethasone began at our institution in 1986. Amniocentesis and CVS samples were referred to our institution from all over the United States and abroad. Some of the fetuses have not yet been born (n = 27), some were aborted (elective, n = 17; spontaneous, n = 11), and some newborns living outside the USA were inaccessible to follow-up (n = 37). The total number of pregnancies that resulted in live births where the mothers, obstetricians, and pediatric endocrinologists gave follow-up information on the newborns and the pregnancies is 532. Genetic counseling was offered for every pregnancy followed, and pregnant mothers were monitored by their own obstetricians. The study was approved by our institution’s review board for human rights in research. Informed consent was obtained from mothers.
Prenatal diagnosis techniques for amniotic fluid were 17-OHP and
4-androsteindione levels (28, 29). DNA analysis was performed by HLA-DR locus and/or direct
DNA analysis of the CYP21 gene (30, 31).
Prenatal treatment protocol
Dexamethasone (20 µg/kg·d in 3 divided doses) was
administered to the pregnant mother before 10 wk gestation, blind to
the affected status of the fetus, to suppress excess adrenal androgen
secretion and prevent virilization should the fetus be an affected
female (Fig. 3
) In 367 of the pregnancies, diagnoses were made by
amniocentesis, and 165 were diagnosed using CVS (Fig. 4). Diagnosis by DNA analysis requires
chorionic villus sampling at 9–11 wk gestation or sampling of amniotic
fluid cells obtained by amniocentesis in the second trimester. The
fetal DNA is used for specific amplification of the CYP21 gene using
PCR (31). If the fetus is determined to be an unaffected
female upon DNA analysis or a male upon karyotype analysis, treatment
is discontinued. Otherwise, treatment is continued to term.
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The 
2 test was used for ANOVA for
maternal side-effects, and the t test was used for
comparison of Prader scores and birth weights in dexamethasone-treated
and nontreated newborns. P < 0.05 was used to identify
significance in all analysis.
Results
Of those 532 pregnancies evaluated, 105 fetuses were found to be
affected with classical 21-OHD (11 were nonclassical). Of the classical
cases, 61 were female, 49 of whom were treated prenatally with
dexamethasone. Dexamethasone administered at or before 9 wk gestation
(25 affected female fetuses) was effective in reducing virilization. Of
these 25, 11 fetuses were born with entirely normal female genitalia,
and 11 were significantly less virilized (Prader stages 1–2) than
those untreated (Fig. 5). Sixteen
affected females treated with dexamethasone full-term had untreated
affected female siblings. In all 16 cases, the external genitalia of
the treated females were less virilized than the genitalia of the
untreated siblings (Fig. 6). Most of the
newborn females whose genitalia were rated Prader stages 3–4 who had
been
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Overall for affected females, the average Prader score for those treated prenatally at or before 9 wk gestation was 0.96, whereas those with no prenatal treatment had an average Prader score of 3.75 (P << 0.003) The external genitalia of affected females prenatally treated at or before 9 wk were less virilized than those of the partially treated affected females (mean Prader score, 3.00; P << 0.008). The Prader scores of partial dexamethasone treatment and no treatment in affected females (mean Prader score, 3.75) are also statistically significant (P = 0.002).
Safety of prenatal therapy
No significant or enduring side-effects were noted in newborns and
children who were prenatally treated. As reported previously
(24), prenatally treated newborns do not differ
significantly in birth weight from untreated newborns. The mean birth
weight for dexamethasone prenatally treated fetuses was 3.34 kg; for
untreated fetuses it was 3.42 kg (P = 0.167; Table 1). The birth length and head
circumference (data not shown) were normal in offspring of
dexamethasone-treated pregnancies compared with those not treated,
which is consistent with other studies where patients and physicians
adhered to the recommended therapeutic protocol (23, 24, 25, 32, 33). A preliminary report of a pilot study of the behavior and
development of 26 prenatally treated children compared with controls
found no negative effects of dexamethasone on developmental milestones
or cognitive development. The pilot study did find increased
internalizing behavioral traits, such as shyness, in the children
prenatally treated with dexamethasone (34). A large
quantitative follow-up study is currently in progress regarding
cognition, gender, temperament, and handedness (an indicator of
prenatal androgen effect) in children and adults who were prenatally
treated with dexamethasone.
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The authors did not find significant differences in side-effects in the
mothers who were treated with dexamethasone from the mothers who were
not treated, except in weight gain (Table 2), edema, and striae. By report, mothers
who were not treated with dexamethasone gained an average of 29.7 lb,
whereas treated mothers gained an average of 36.8 lb, which was
statistically significant (P < 0.005). There was a
statistically significant difference found for the presence of striae
(P = 0.01) and edema (P = 0.02). It is
of interest to note, however, that of 21 mothers treated with
dexamethasone throughout pregnancy because the fetus was determined to
be an affected female, 10 described the striae as being more severe
compared with their prior pregnancy with the untreated proband, whereas
10 described the striae as the same, and 1 as less. There were 4
pregnancies treated until term with dexamethasone for an affected
female fetus in which the mother reported no striae in the treated
pregnancy or any prior pregnancy. There was not a statistically
significant difference found for hypertension (P = 0.5)
or gestational diabetes (P = 0.34) in the treated or
untreated pregnancy groups. All mothers who received prenatal
dexamethasone (partial and full term) treatment stated that they would
take dexamethasone again in the event of a future pregnancy.
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With regard to the Mendelian ratio of our patients, 33% were
homozygous affected, 44% were heterozygous, and 23% were homozygous
normal. This does differ from the expected Mendelian ratio of 1:2:1. It
should be noted that 65% of the affected babies were female. This is a
much greater proportion of females and a significant difference from
the 1:1 expected ratio. A possible explanation for this is that genital
ambiguity, which only occurs in females, is more likely to result in a
referral for further investigation at our institution after
amniocentesis or CVS. The frequency of mutations finds that the intron
2 homozygous mutation remains the most common classic CAH mutation
(1) (Table 3).
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Prevention of genital virilization in female newborns with classic CAH has significant implications. Parents who are carriers for 21-hydroxylase mutations have less anxiety carrying an affected female because the extent of genital virilization will be minimal or nonexistent with prenatal treatment. The implications for the prenatally treated child center on the benefits of less virilized genitalia, the diminished need for future vaginoplasty and its resulting psychological impact. Although corrective surgery techniques for genital ambiguity have improved (i.e. preserving the sensitivity of the clitoris), there are insufficient data on long-term outcome, including the need for additional surgery, the adequacy of sexual functioning, and overall patient satisfaction. In addition, prenatal treatment avoids a male sex assignment to virilized female newborns and has been suggested to prevent the gender ambiguity sometimes seen in CAH females, which has been attributed in part to the high level androgen exposure of the brain during differentiation (35).
Some researchers (36, 37, 38) have questioned the safety of prenatal treatment for mother and fetus, citing experiments in mice or rare and isolated cases of adverse events in newborns and children. Corticosteroid use in human pregnancy has been categorized by Shepard’s Catalog of Teratogenic Agents (39) as not highly dangerous, and the risk of congenital malformations owing to prenatal exposure to corticosteroid use in human pregnancy is not significant (40). The isolated cases in which adverse events occurred, however, have not been attributed with certainty to the dexamethasone treatment (25, 32, 33, 41, 42, 43). In addition, animal experiments that have shown low birth weight and health problems (i.e. growth retardation, hyperinsulinemia, and hypertension) used excess glucocorticoid in dosages 4–16 times the human dose (44, 45, 46, 47). Several of these studies (45, 46, 47) used rodents, which are a poor model for human glucocorticoid action, as the rodent does not have receptors for cortisol, only corticosterone. This study and other large human studies of prenatal treatment for 21-hydroxylase deficiency using dexamethasone demonstrate that dexamethasone does not have teratogenic effects when used according to the protocol (25, 32, 33).
Studies of prenatal therapy for CAH before 1993 must be viewed with caution, as it was common practice to stop dexamethasone treatment to determine hormone values in amniotic fluid and because protocols varied among institutions. Discontinuing dexamethasone treatment for an even short period during the stages of sexual differentiation was seen to increase the likelihood of genital virilization in the affected female newborns in our study and others (48). We are in agreement with Seckl and Miller (36) in that prenatal dexamethasone treatment for CAH should only be undertaken when the follow-up in the newborn is documented by competent pediatricians experienced with the disease. Only then can the benefit of prenatal treatment be compared with other treatments available for genital ambiguity.
Based on our experience, proper prenatal diagnosis and treatment of 21-OHD is safe and effective in significantly reducing or eliminating virilization in the affected female. The risk to benefit ratio in view of no enduring side-effects in mother or child favors prenatal treatment. Of the monogenic disorders, steroid 21-OHD is one of the few in which prenatal treatment is effective and influences postnatal life.
Acknowledgments
Footnotes
This work was supported by USPHS Grant HD-00072 and General Clinical Research Center Grant 06020.
Abbreviations: CAH, Congenital adrenal hyperplasia; CVS, chorionic villus sampling; HLA, human leukocyte antigen; 21-OHD, 21-hydroxylase deficiency; 17-OHP, 17-hydroxyprogesterone.
Received March 21, 2001.
Accepted August 8, 2001.
References
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|
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|
|
 |
|
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|
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 |
|
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|
|
|
|
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|
|
|
|
 |
|
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|
|
|
|
|
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T. Tukel, O. Uyguner, J. Q. Wei, M. Yuksel-Apak, N. Saka, D. X. Song, H. Kayserili, F. Bas, H. Gunoz, R. C. Wilson, et al. A Novel Semiquantitative Polymerase Chain Reaction/Enzyme Digestion-Based Method for Detection of Large Scale Deletions/Conversions of the CYP21 Gene and Mutation Screening in Turkish Families with 21-Hydroxylase Deficiency J. Clin. Endocrinol. Metab., December 1, 2003; 88(12): 5893 - 5897. [Abstract] [Full Text] [PDF]
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|
 |
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|
|
 |
|
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