Structure-based analysis of five novel disease-causing mutations in 21-hydroxylase-deficient patients.

Congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency is the most frequent inborn error of metabolism, and accounts for 90-95% of CAH cases. The affected enzyme, P450C21, is encoded by the CYP21A2 gene, located together with a 98% nucleotide sequence identity CYP21A1P pseudogene, on chromosome 6p21.3. Even though most patients carry CYP21A1P-derived mutations, an increasing number of novel and rare mutations in disease causing alleles were found in the last years. In the present work, we describe five CYP21A2 novel mutations, p.R132C, p.149C, p.M283V, p.E431K and a frameshift g.2511_2512delGG, in four non-classical and one salt wasting patients from Argentina. All novel point mutations are located in CYP21 protein residues that are conserved throughout mammalian species, and none of them were found in control individuals. The putative pathogenic mechanisms of the novel variants were analyzed in silico. A three-dimensional CYP21 structure was generated by homology modeling and the protein design algorithm FoldX was used to calculate changes in stability of CYP21A2 protein. Our analysis revealed changes in protein stability or in the surface charge of the mutant enzymes, which could be related to the clinical manifestation found in patients.

Congenital adrenal hyperplasia clinical characteristics and genotype in newborn, childhood and adolescence.

Congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency is a disorder which can adopt three clinical expressions: two classical forms -salt-wasting (SW), with residual enzymatic activity (EA) < or = 1% and simple virilizing (SV), with EA 1-2%- and a mild late onset or nonclassical (NC) form, with EA 10-60%. Our objective is to describe clinical characteristics, growth, and bone mass in a group of patients affected by 21-hydroxylase deficiency. Besides, molecular genetics studies were performed in patients, and also when available in their parents and siblings. Nine patients with neonatal diagnosis and 8 with pre or postpubertal diagnosis were studied. Analyses of 10-point mutations in the CYP21A2 gene were performed. We found that all the patients with the classical expression, except one with a de novo mutation R356W in one allele, were fully genotyped with predictive < 2% EA mutations. Signs of hyperandrogenism were present in 5/6 NC patients; one was diagnosed by searching for mutations in asymptomatic siblings. All the NC patients were compound heterozygotes carrying V281L mutation in one allele and a predictive low EA in the other, except for one not yet determined. In patients with neonatal diagnosis, mean height was low at one year of age, though it showed a significant increase before the onset of puberty. We conclude that neonatal diagnosis of classical CAH allows an adequate follow up enhancing growth. Molecular analyses of all members of an affected family may disclose asymptomatic patients. The presence of de novo mutations, as well as, the presence of mutations with low predicted EA in NC patients reinforces the importance of genotyping for appropriate genetic counseling. In fully genotyped NC patients, the lowest value of ACTH-stimulated 17OHP was 14 ng/ml. Lower cut-off values might overestimate the diagnosis of the NC form.

Congenital adrenal hyperplasia clinical: characteristics and genotype in newborn, childhood and adolescence / Hiperplasia suprarrenal congenital: características clínicas, seguimiento y genotipo en la etapa perinatal, la niñez y la adolescencia

Congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency is a disorder which can adopt three clinical expressions: two classical forms –salt-wasting (SW), with residual enzymatic activity (EA) < 1% and simple virilizing (SV), with EA 1-2%– and a mild late onset or nonclassical (NC) form, with EA 10-60%. Our objective is to describe clinical characteristics, growth, and bone mass in a group of patients affected by 21-hydroxylase deficiency. Besides, molecular genetics studies were performed in patients, and also when available in their parents and siblings. Nine patients with neonatal diagnosis and 8 with pre or postpubertal diagnosis were studied. Analyses of 10-point mutations in the CYP21A2 gene were performed. We found that all the patients with the classical expression, except one with a de novo mutation R356W in one allele, were fully genotyped with predictive < 2% EA mutations. Signs of hyperandrogenism were present in 5/6 NC patients; one was diagnosed by searching for mutations in asymptomatic siblings. All the NC patients were compound heterozygotes carrying V281L mutation in one allele and a predictive low EA in the other, except for one not yet determined. In patients with neonatal diagnosis, mean height was low at one year of age, though it showed a significant increase before the onset of puberty. We conclude that neonatal diagnosis of classical CAH allows an adequate follow up enhancing growth. Molecular analyses of all members of an affected family may disclose asymptomatic patients. The presence of de novo mutations, as well as, the presence of mutations with low predicted EA in NC patients reinforces the importance of genotyping for appropriate genetic counseling. In fully genotyped NC patients, the lowest value of ACTH-stimulated 17OHP was 14 ng/ml. Lower cut-off values might overestimate the diagnosis of the NC form.

La hiperplasia suprarrenal congénita por déficit de 21-hidroxilasa presenta tres formas clínicas: dos clásicas, perdedora de sal, con actividad enzimática (AE) < 1% y virilizante simple, con AE 1-2% y una no clásica, con AE 10-60%. Nuestro objetivo es describir las características clínicas y el genotipo de un grupo de pacientes con hiperplasia suprarrenal congénita; este último también sedeterminó en todos los miembros de la familia. Se estudiaron 9 pacientes diagnosticados en la etapa perinatal y 8 durante la etapa pre y postpuberal. Se analizaron diez mutaciones en el gen CYP21A2 y se evaluó crecimiento y densidad mineral ósea. Once pacientes presentaron la forma clásica: 9 con diagnóstico perinatal y 2 diagnosticados más tardíamente, uno de ellos con agrandamiento testicular por restos adrenales. Todos los pacientes, salvo 1 con una mutación de novo R356W en un alelo, presentaron ambos alelos mutados con un genotipo que predice AE < 2%. Seis pacientes presentaron la forma no clásica, todos con signos clínicos de hiperandrogenismo salvo un familiar asintomático que se diagnosticó por el estudio molecular. Todos, a excepción de uno con un alelo aún no determinado, presentaron la mutación V281L acompañada de otra que predice AE < 2%. Durante la evolución de los pacientes de diagnóstico perinatal se observó talla baja al año con recuperación de la misma en la etapa prepuberal. La densidad mineral ósea fue normal. Podemos concluir que el diagnóstico en la etapa perinatal en pacientes con la forma clásica posibilita un mejor seguimiento y crecimiento. La genotipificación de todos los miembros de una familia permite el diagnóstico de formas asintomáticas. La presencia de mutaciones de novo y de un alelo con una mutación que predice baja AE en los pacientes con forma no clásica, refuerza la importancia de la genotipificación para un adecuado asesoramiento genético.

Congenital adrenal hyperplasia clinical: characteristics and genotype in newborn, childhood and adolescence / Hiperplasia suprarrenal congenital: características clínicas, seguimiento y genotipo en la etapa perinatal, la niñez y la adolescencia

Congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency is a disorder which can adopt three clinical expressions: two classical forms ¹salt-wasting (SW), with residual enzymatic activity (EA) < 1% and simple virilizing (SV), with EA 1-2%¹ and a mild late onset or nonclassical (NC) form, with EA 10-60%. Our objective is to describe clinical characteristics, growth, and bone mass in a group of patients affected by 21-hydroxylase deficiency. Besides, molecular genetics studies were performed in patients, and also when available in their parents and siblings. Nine patients with neonatal diagnosis and 8 with pre or postpubertal diagnosis were studied. Analyses of 10-point mutations in the CYP21A2 gene were performed. We found that all the patients with the classical expression, except one with a de novo mutation R356W in one allele, were fully genotyped with predictive < 2% EA mutations. Signs of hyperandrogenism were present in 5/6 NC patients; one was diagnosed by searching for mutations in asymptomatic siblings. All the NC patients were compound heterozygotes carrying V281L mutation in one allele and a predictive low EA in the other, except for one not yet determined. In patients with neonatal diagnosis, mean height was low at one year of age, though it showed a significant increase before the onset of puberty. We conclude that neonatal diagnosis of classical CAH allows an adequate follow up enhancing growth. Molecular analyses of all members of an affected family may disclose asymptomatic patients. The presence of de novo mutations, as well as, the presence of mutations with low predicted EA in NC patients reinforces the importance of genotyping for appropriate genetic counseling. In fully genotyped NC patients, the lowest value of ACTH-stimulated 17OHP was 14 ng/ml. Lower cut-off values might overestimate the diagnosis of the NC form.(AU)

La hiperplasia suprarrenal congénita por déficit de 21-hidroxilasa presenta tres formas clínicas: dos clásicas, perdedora de sal, con actividad enzimática (AE) < 1% y virilizante simple, con AE 1-2% y una no clásica, con AE 10-60%. Nuestro objetivo es describir las características clínicas y el genotipo de un grupo de pacientes con hiperplasia suprarrenal congénita; este último también sedeterminó en todos los miembros de la familia. Se estudiaron 9 pacientes diagnosticados en la etapa perinatal y 8 durante la etapa pre y postpuberal. Se analizaron diez mutaciones en el gen CYP21A2 y se evaluó crecimiento y densidad mineral ósea. Once pacientes presentaron la forma clásica: 9 con diagnóstico perinatal y 2 diagnosticados más tardíamente, uno de ellos con agrandamiento testicular por restos adrenales. Todos los pacientes, salvo 1 con una mutación de novo R356W en un alelo, presentaron ambos alelos mutados con un genotipo que predice AE < 2%. Seis pacientes presentaron la forma no clásica, todos con signos clínicos de hiperandrogenismo salvo un familiar asintomático que se diagnosticó por el estudio molecular. Todos, a excepción de uno con un alelo aún no determinado, presentaron la mutación V281L acompañada de otra que predice AE < 2%. Durante la evolución de los pacientes de diagnóstico perinatal se observó talla baja al año con recuperación de la misma en la etapa prepuberal. La densidad mineral ósea fue normal. Podemos concluir que el diagnóstico en la etapa perinatal en pacientes con la forma clásica posibilita un mejor seguimiento y crecimiento. La genotipificación de todos los miembros de una familia permite el diagnóstico de formas asintomáticas. La presencia de mutaciones de novo y de un alelo con una mutación que predice baja AE en los pacientes con forma no clásica, refuerza la importancia de la genotipificación para un adecuado asesoramiento genético.(AU)

Classical and nonclassical 21-hydroxylase deficiency: a molecular study of Argentine patients.

OBJECTIVE: To characterize the molecular basis of the 21-hydroxylase deficiency in a group of Argentine patients presenting the classical and nonclassical forms of the disease. DESIGN: To analyse the frequency of point mutations in the CYP21 gene by DNA amplification and mutation detection. PATIENTS: Forty-one patients from 36 nonrelated families: 25 nonclassical (NC), 11 salt-wasting (SW) and five simple virilizing (SV). A total of 27 parents and 13 nonaffected siblings were also analysed. MEASUREMENTS: Basal steroid hormones and 17-hydroxyprogesterone levels following adrenal stimulation with adrenocorticotrophic hormone were measured, together with an analysis of 10 point mutations in the CYP21 gene. RESULTS: A total of 83% and 74.4% classical and nonclassical chromosomes, respectively, were characterized. The intron 2 mutation was the most prevalent among classical alleles. In addition, a high frequency for R356W was observed in both groups (13.3 and 6.9%, respectively), while V281L was the most frequent mutation among the nonclassical patients with a frequency of 39.5%. No alleles containing P30L were observed, and one de novo mutation (R356W) was found. A total of 68.3% patients were fully genotyped, and all but one showed no genotype/phenotype discrepancy. Though the cut-off value for post-ACTH 17-hydroxyprogesterone stimulation was 30.25 nmol/l (10.00 microg/l), the lowest value observed in the fully genotyped nonclassical group was 42.35 nmol/l (14.00 microg/l). CONCLUSIONS: The high number of unidentified alleles in the nonclassical group suggests that less frequent mutations, or the presence of new ones, might be the cause of the disease in the Argentine population. Alternatively, the cut-off value in the ACTH-stimulated 17-hydroxyprogesterone test might overestimate the diagnosis of the nonclassical form by including some patients with heterozygous status.