21-Hydroxylase deficiency: from molecular genetics to clinical presentation

Genetic architecture of acne vulgaris

Acne vulgaris is a ubiquitary skin disease characterized by chronic inflammation of the pilosebaceous unit resulting from bacterial colonization of hair follicles by Propionibacterium acnes, androgen-induced increased sebum production, altered keratinization and inflammation. Here, we review our current understanding of the genetic architecture of this intriguing disease. We analysed genomewide association studies (GWAS) and candidate genes studies for acne vulgaris. Moreover, we included GWAS studies for the associated disease polycystic ovary syndrome (PCOS). Overall, the available data revealed sixteen genetic loci flagged by single nucleotide polymorphisms (SNPs), none of which has been confirmed yet by independent studies. Moreover, a GWAS for PCOS identified 21 susceptible loci. The genetic architecture is complex which has been revealed by GWAS. Further and larger studies in different populations are required to confirm or disprove results from candidate gene studies as well to identify signals that may overlap between different populations. Finally, studies on rare genetic variants in acne and associated diseases like PCOS may deepen our understanding of its pathogenesis.

Genotype, phenotype and hormonal levels correlation in non-classical congenital adrenal hyperplasia

Non-classical congenital adrenal hyperplasia (NCAH) is a morbid condition sustained by the reduced function of one of the enzymes involved in the adrenal steroid biosynthesis pathway, mainly the 21-hydroxylase. Different degrees of enzyme activity impairment determine different clinical pictures, with childhood or post-pubertal onset. The aim of this study was to evaluate the relationship between genotype, phenotype, and adrenal hormonal levels in a group of 66 patients affected by NCAH attending outpatient pediatric or endocrinological Clinics. Our findings show that age at pubarche/menarche was significantly younger, height SD score) and Δ bone age-chronological age were significantly higher in patients with a more severe enzyme activity impairment, while cutaneous androgenization and menstrual irregularities in post-pubertal girls were not related to the grading of genotype.

An update to 21-hydroxylase deficient congenital adrenal hyperplasia

Congenital adrenal hyperplasia (CAH) due to deficiency of the enzyme 21-hydroxylase (21-OH) is distinguished in classical (C-CAH) and non-classical form (NC-CAH), and it is also one of the most common autosomal recessive inherited disorders in humans. The prevalence of C-CAH is between 1:10,000 and 1:15,000 among the live neonates of North America and Europe while the NC-CAH occurs in approximately 0.2% of the general white population. The highest incidence of CAH (1:282 and 1:2141, respectively) has been evaluated in Yupik Eskimos in Alaska and in the populations of the island La Reunion (France), while the lower was detected in New Zealand newborns (0.3%). Nowadays, it has been established that except for the adrenal cortex in CAH cases, the adrenal medulla was also affected. In human 21-OH deficient adrenal gland it has been discovered that not only the chromaffin cells formed extensive neurites, expanding between adrenocortical cells, but also that the adrenal androgens promote outgrowth, whereas glucocorticoids preserve neuroendocrine cells. It seems that normal cortisol secretion by the adrenal cortex is necessary for adrenomedullary organogenesis. The synthesis of 21-OH is controlled by the active CYP21A2 gene located at a distance of 30 kb from a highly homologous pseudogene designated CYP21A1P.

The prevalence of non-classical congenital adrenal hyperplasia due to 21-hydroxylase deficiency in Greek women with hirsutism and polycystic ovary syndrome

The study was aimed to find out the prevalence of non-classical congenital adrenal hyperplasia (NC-CAH) due to 21-hydroxylase deficiency (21-OHdef) among Greek women with hirsutism and polycystic ovary syndrome (PCOS) and to compare the results of ACTH stimulated 17-hydroxyprogesterone 60 min (17-OHP60) values, with human leukocyte antigens (HLA) phenotypes, in any patient diagnosed as having NC-CAH. One hundred and seven women with hirsutism and PCOS were included in the study. All were presented at the Reproductive Endocrinology Outpatient Clinic with hirsutism and PCOS. After ACTH stimulation test, 10 women were diagnosed as having NC-CAH because of high 17-OHP60 values >or=36 nmol/l, and 97 as having PCOS. Ten (10.3%) of the 97 women presented hormonal findings compatible with adrenal hyper-response due to ACTH testing, because of hyperstimulated 17-OHP60 values >or=21 nmol/l and <32 nmol/l. The HLA typing of 10 patients with NC-CAH revealed the phenotypes B14, DR1, B35, B7 and B44 which present positively genetic linkage disequilibrium with 21-OHdef, as reported in the literature.

IN CONCLUSION

In Greek women with hirsutism and PCOS we have found that: a. The prevalence of NC-CAH among these women is relatively high and reaches at 10%. b. The HLA phenotypes B(14), DR(1), B(35), B(7) and B44 were found in high frequency in these NC-CAH patients. c. Adrenal NC-CAH due to 21-OHdef as well as adrenal hyperactivity, revealed after ACTH testing, constitutes an important reason of hirsutism and PCOS in these Greek women and both reach a rate of 20%.

First case of V281+I172N/V281L CYP21A2 genotype associated with congenital adrenal hyperplasia form. A case report from South Italy

OBJECTIVES

To report a first case of 21-hydroxylase deficiency associated with a new genotype determined by V281+I172N/V281L mutations of the CYP21A2 gene.

DESIGN AND METHODS

Direct genetic sequencing of CYP21A2 gene was performed.

RESULTS

Both siblings had the same genotype, namely V281+I172N/V281L, while their parents resulted as V281L and V281+I172N carriers, respectively.

CONCLUSIONS

V281+I172N/V281L genotype should be included in the panel of mutations associated with the non-classical forms of 21-hydroxylase deficiency.

Hiperplasia adrenal congênita por deficiência da 21-hidroxilase, forma clássica: estudo da freqüência em famílias de indivíduos afetados

OBJETIVOS: Analisar a freqüência de indivíduos afetados e das formas clínicas da doença, de acordo com o gênero e a taxa de consangüinidade, em famílias com hiperplasia adrenal congênita (HAC) por deficiência da enzima 21-hidroxilase, forma clássica (HAC-D21-OHC). MÉTODOS: A casuística foi composta por 58 famílias com 79 indivíduos afetados (67 vivos e 12 mortos) com pais normais e pelo menos um filho afetado vivo com diagnóstico comprovado da doença. A freqüência de indivíduos afetados foi avaliada pelas técnicas de Haldane e Hogben, com análise por seleção truncada. Também foram avaliadas a história parental de consangüinidade e a freqüência de homozigose de mutações no gene CYP21A2, bem como a forma clínica da doença e a distribuição por gênero. RESULTADOS: Dez famílias apresentaram história de consangüinidade entre os pais e mais cinco com homozigose no estudo molecular. A freqüência de indivíduos afetados nas irmandades avaliadas foi de 23,5%, semelhante à esperada de 25%; no entanto, com distribuição heterogênea. Quanto às formas clínicas, 56 (70%) eram perdedores de sal (25M:31F) e 23 (30%) virilizantes simples (10M:13F), não sendo observada diferença na distribuição entre os gêneros. CONCLUSÕES: Estes dados confirmam que a HAC-D21-OHC apresenta padrão de herança monogênica autossômica recessiva, com freqüência de 23,5% na irmandade de indivíduos afetados, elevada taxa de consangüinidade e proporção semelhante entre os gêneros, porém com distribuição heterogênea no número de casos nas irmandades e predomínio da forma clínica perdedora de sal.

Polymorphisms in the glucocerebrosidase gene and pseudogene urge caution in clinical analysis of Gaucher disease allele c.1448T>C (L444P)

Background

Gaucher disease is a potentially severe lysosomal storage disorder caused by mutations in the human glucocerebrosidase gene (GBA). We have developed a multiplexed genetic assay for eight diseases prevalent in the Ashkenazi population: Tay-Sachs, Gaucher type I, Niemann-Pick types A and B, mucolipidosis type IV, familial dysautonomia, Canavan, Bloom syndrome, and Fanconi anemia type C. This assay includes an allelic determination for GBA allele c.1448T>C (L444P). The goal of this study was to clinically evaluate this assay.

Methods

Biotinylated, multiplex PCR products were directly hybridized to capture probes immobilized on fluorescently addressed microspheres. After incubation with streptavidin-conjugated fluorophore, the reactions were analyzed by Luminex IS100. Clinical evaluations were conducted using de-identified patient DNA samples.

Results

We evaluated a multiplexed suspension array assay that includes wild-type and mutant genetic determinations for Gaucher disease allele c.1448T>C. Two percent of samples reported to be wild-type by conventional methods were observed to be c.1448T>C heterozygous using our assay. Sequence analysis suggested that this phenomenon was due to co-amplification of the functional gene and a paralogous pseudogene (ΨGBA) due to a polymorphism in the primer-binding site of the latter. Primers for the amplification of this allele were then repositioned to span an upstream deletion in the pseudogene, yielding a much longer amplicon. Although it is widely reported that long amplicons negatively impact amplification or detection efficiency in recently adopted multiplex techniques, this assay design functioned properly and resolved the occurrence of false heterozygosity.

Conclusion

Although previously available sequence information suggested GBA gene/pseudogene discrimination capabilities with a short amplified product, we identified common single-nucleotide polymorphisms in the pseudogene that required amplification of a larger region for effective discrimination.