High frequency of non-classical congenital adrenal hyperplasia form among children with persistently elevated levels of 17-hydroxyprogesterone after newborn screening.

Background Early diagnosis after newborn screening (NBS) for congenital adrenal hyperplasia (CAH) allows proper treatment, reducing mortality rates and preventing development of hyperandrogenic manifestations and incorrect sex assignment at birth. Despite the high NBS sensitivity to detect CAH classical forms, one of the main issues is identifying asymptomatic children who remained with increased 17-hydroxyprogesterone (17-OHP) levels. In this study, we aimed to contribute to understanding the diagnosis of these children. Methods Children with increased serum 17-OHP levels, and without disease-related clinical features during follow-up, underwent the entire CYP21A2 gene sequencing and multiplex ligation-dependent probe amplification (MLPA) analysis (SALSA MLPA P050B CAH). Patients' genotypes were subsequently sorted as compatible with CAH disease, and children were evaluated to determine the clinical status. Results During the study period, 106,476 newborns underwent CAH NBS. During follow-up, 328 children (0.3%) were identified as having false-positive tests and 295 were discharged after presenting with 17-OHP levels within reference values. Thirty-three remained asymptomatic and with increased serum 17-OHP levels after a mean follow-up of 3.4 years, and were subjected to molecular analysis. Seventeen out of the 33 children carried mutations: seven in the heterozygous state, nine carried non-classical genotypes and the remaining child carried a classical genotype. Conclusions We found a high frequency of non-classical CAH (NCCAH) diagnosis among children with persistent elevation of 17-OHP levels. Our findings support molecular study as decisive for elucidating diagnosis in these asymptomatic children. Molecular analysis as a confirmatory test is relevant to guide their follow-up, allows genetic counseling and avoids over treating NCCAH form.

Heterozygous Nonsense Mutation in the Androgen Receptor Gene Associated with Partial Androgen Insensitivity Syndrome in an Individual with 47,XXY Karyotype.

There are only 2 patients with 47,XXY karyotype and androgen receptor (AR) gene mutation reported in the literature, and both are diagnosed as complete androgen insensitivity syndrome (CAIS). We report a 22-year-old female with 47,XXY karyotype and atypical external genitalia. Sequencing of AR revealed the heterozygous p.Asn849Lys*32 mutation, and extensive X chromosome microsatellite analysis showed homozygosity for Xp and heterozygosity for Xq, suggesting partial X maternal isodisomy. Partial androgen insensitivity syndrome (PAIS) developed in this case, probably because of the presence of the heterozygous AR mutation and random X- inactivation of the healthy allele. This is the first report of a female patient with 47,XXY karyotype and PAIS phenotype.

Molecular CYP21A2 diagnosis in 480 Brazilian patients with congenital adrenal hyperplasia before newborn screening introduction.

BACKGROUND: Most congenital adrenal hyperplasia (CAH) patients carry CYP21A2 mutations derived from conversion events involving the pseudogene, and the remaining carry new mutations. OBJECTIVE: To review causal mutations and genotype-phenotype correlation in 480 Brazilian patients. METHODS: DNA was extracted from 158 salt-wasters (SWs), 116 simple virilizing (SV), and 206 nonclassical (NC) patients. Fourteen point mutations were screened by allele-specific PCR, large rearrangements by Southern blotting/MLPA, and sequencing was performed in those with incomplete genotype. The gene founder effect was analyzed by microsatellite studies. Patients were divided into six genotypes (Null; A: <2%; B: 3-7%; C: >20% of residual enzymatic activity (EA); D: unknown EA; E: incomplete genotype). RESULTS: Targeted methodologies defined genotype in 87.6% of classical and in 80% of NC patients and the addition of sequencing in 100 and 83.5%, respectively. The most frequent mutations were p.V281L (26.6% of alleles), IVS2-13A/C>G (21.1%), and p.I172N (7.5%); seven rare mutations and one novel mutation (p.E351V) were identified. Gene founder effect was observed in all but one (p.W19X) mutation. Null, A, B, and C genotypes correlated with SW (88%), SW (70%), SV (98%), and NC forms (100%), respectively. In group D, the p.E351V mutation correlated with classical form and group E comprised exclusively NC-patients. ACTH-stimulated 17OHP level of 44.3ng/mL was the best cutoff to identify NC-patients carrying severe mutations. CONCLUSIONS: We identified a good genotype-phenotype correlation in CAH, providing useful data regarding prediction of disease's severity; moreover, we suggest that ACTH-stimulated 17OHP levels could predict carrier status for severe mutations. Sequencing is essential to optimize molecular diagnosis in Brazilian CAH patients.