title: Molecular genetic analysis in 93 patients and 193 family members with classical congenital adrenal hyperplasia due to 21-hydroxylase deficiency in Croatia.
abstract: Congenital adrenal hyperplasia owing to 21-hydroxylase deficiency is caused by mutation in the CYP21A2 gene. The frequency and spectrum of CYP21A2 mutations and genotype-phenotype correlations among different populations are variable. Aim of this study was to define mutation frequency and spectrum of CYP21A2 gene mutations in patients with classical 21-hydroxylase deficiency (21OHD) and their family members in Croatia and study genotype-phenotype correlation. Clinical features and mutations of CYP21A2 gene in 93 unrelated 21OHD patients and 193 family members were examined. In this cohort, 66 patients were affected with salt wasting (SW) form, and 27 were affected with simple virilizing (SV) form of the disease. Mutations were identified in both alleles (67% compound heterozygous and 33% homozygous) in 91 of 93 patients. Deletions and conversions were found in 18.8% and point mutations in 79.6% alleles. Mutations in 3 alleles (1.6%) remained unidentified (in one patient we found only one, while in other no mutations were found at all). The most common point mutations were Intron 2 splice mutation IVS2-13 A/C>G (35.5%) and p.R357W (16.7%). Genotypes were categorized into Groups 0, A, B and C according to the extent of enzyme impairment. Genotype-phenotype concordance was 100%, 85% and 75% for Groups 0, A and B, respectively. Since only classical 21OHD patients were studied, Group C comprised solely p.P31L mutation and had 73% patients with SV and 27% with SW phenotype. Intrafamilial phenotypic variability was found in two families. CYP21A2 genetic analysis in 193 family members showed that 126 parents were heterozygous carriers, 3 were newly discovered patients, 2 fathers were not biological parents, and mutations were not detected in 3. Among 59 siblings, 32 were heterozygous carriers, 15 carried normal alleles, and 12 were patients (4 newly diagnosed). Genotype-phenotype divergence observed in this study suggests caution in preconceptional counseling and prenatal diagnosis of CAH. High frequency of p.R357W mutation was found in Croatian patients with classical 21-OHD. Genotyping of family members discovered new patients and thus avoided pitfalls in genetic counseling when the parents were found to be affected.
authors.affiliation: Department of Pediatrics, Clinical Hospital Centre Zagreb, University of Zagreb Medical School, Zagreb, Croatia. Electronic address: katja.dumic@gmail.com.
authors.forename: Katja K
authors.initials: KK
authors.lastname: Dumic
authors.affiliation: Tissue Typing Centre, Department of Transfusion Medicine and Transplantation Biology, Department of Laboratory Medicine, Clinical Hospital Centre Zagreb, University of Zagreb Medical School, Zagreb, Croatia.
authors.forename: Zorana
authors.initials: Z
authors.lastname: Grubic
authors.affiliation: Steroid Disorders Program, Department of Pediatrics, Mount Sinai School of Medicine New York, NY, USA.
authors.forename: Tony
authors.initials: T
authors.lastname: Yuen
authors.affiliation: Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, SC, USA.
authors.forename: Robert C
authors.initials: RC
authors.lastname: Wilson
authors.affiliation: Endocrinological Laboratory, Department of Laboratory Medicine, Clinical Hospital Centre Zagreb, University of Zagreb Medical School, Zagreb, Croatia.
authors.forename: Vesna
authors.initials: V
authors.lastname: Kusec
authors.affiliation: Department of Medical Genetics, Department of Pediatrics, Children's Hospital Zagreb, University of Zagreb Medical School, Zagreb, Croatia.
authors.forename: Ingeborg
authors.initials: I
authors.lastname: Barisic
authors.affiliation: Tissue Typing Centre, Department of Transfusion Medicine and Transplantation Biology, Department of Laboratory Medicine, Clinical Hospital Centre Zagreb, University of Zagreb Medical School, Zagreb, Croatia.
authors.forename: Katarina
authors.initials: K
authors.lastname: Stingl
authors.affiliation: Department of Medical Genetics, Department of Pediatrics, Children's Hospital Zagreb, University of Zagreb Medical School, Zagreb, Croatia.
authors.forename: Ivona
authors.initials: I
authors.lastname: Sansovic
authors.affiliation: Department of Pediatrics, Clinical Hospital Centre Split, University of Split Medical School, Split, Croatia.
authors.forename: Veselin
authors.initials: V
authors.lastname: Skrabic
authors.affiliation: University of Zagreb Medical School, Zagreb, Croatia.
authors.forename: Miroslav
authors.initials: M
authors.lastname: Dumic
authors.affiliation: Steroid Disorders Program, Department of Pediatrics, Mount Sinai School of Medicine New York, NY, USA.
authors.forename: Maria I
authors.initials: MI
authors.lastname: New
mesh_terms: D000312:Adrenal Hyperplasia, Congenital / Q000208:ethnology / Q000235:genetics*; D000483:Alleles; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D017523:Croatia; D005260:Female; D056726:Genetic Association Studies; D005838:Genotype; D006680:HLA Antigens / Q000737:chemistry; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D009154:Mutation; D010375:Pedigree; D010641:Phenotype; D017354:Point Mutation; D035781:Siblings; D013255:Steroid 21-Hydroxylase / Q000235:genetics*
chemical_list: D006680:HLA Antigens; C531510:CYP21A2 protein, human; D013255:Steroid 21-Hydroxylase
keywords: 21-Hydroxylase deficiency; CYP21A2 gene; Genotype; Phenotype