Genotype-phenotype concordance in 21-hydroxylase deficiency: de-identified dataset from a single-centre cohort in the Eastern Black Sea region of Turkiye

De-identified molecular, clinical and biochemical dataset for 61 individuals referred for CYP21A2 analysis to a single medical genetics centre in the Eastern Black Sea region of Türkiye between 1 January 2022 and 1 October 2025, either because of a clinical suspicion of congenital adrenal hyperplasia or as part of cascade screening after a CYP21A2 variant was identified in a relative. The cohort comprises 13 families with two or more tested members (F01–F13) and 18 singletons (S01–S18). Thirteen distinct CYP21A2 variants were identified, accounting for 66 pathogenic alleles. The workbook contains eleven tables plus a README sheet and a data dictionary: individual-level genotypes, a variant catalogue with ACMG/AMP classifications, family segregation data, the available hormonal profiles, the genotype–phenotype concordance assessment, the differential diagnoses of symptomatic CYP21A2-negative individuals, and cohort-level molecular epidemiology summaries. Methods: full-gene sequencing of CYP21A2 (NM_000500.9) and MLPA (SALSA Probemix P050, MRC Holland). Variants classified per ACMG/AMP criteria with reference to ClinVar and the EMQN best-practice guidelines for 21-hydroxylase deficiency. Assembly GRCh38. Ethics: approved by the Non-Interventional Scientific Research Ethics Committee of Ordu University (meeting no. 10, 22 May 2026; decision no. 2026/144), conducted in accordance with the Declaration of Helsinki. Consent waived for retrospective analysis of de-identified records. Caveat: a substantial part of the cohort was ascertained through cascade family screening, which enriches for carriers. The allele frequencies describe this referral cohort and must not be read as population frequencies. Variants were also submitted to ClinVar under submission SUB16340115 (release status Public); SCV accessions pending. Version 1.1: zygosity value added for one record (F01-3); no other changes.