17α Hydroxylase/17,20 lyase deficiency: clinical features and genetic insights from a large Turkey cohort.

Purpose: 17α Hydroxylase/17,20 lyase deficiency (17OHD) is a rare form of congenital adrenal hyperplasia, typically diagnosed in late adolescence with symptoms of pubertal delay and hypertension. This study aimed to determine the clinical and laboratory characteristics of 17OHD cases and gather data on disease management.

Methods: Data from 97 nationwide cases were analyzed using the CEDD-NET web system. Diagnostic, follow-up findings, and final heights of patients were evaluated.

Results: Mean age at admission was 13.54 ± 4.71 years, with delayed puberty as the most common complaint. Hypertension was detected in 65% at presentation; hypokalemia was present in 34%. Genetic analysis revealed Exon 1-6 homozygous deletion as the most frequent mutation, identified in 42 cases. Hydrocortisone replacement was universal; pubertal replacement was administered to 66 cases. Antihypertensive treatment was required in 57 (90%) patients. Thirty-seven cases reached final height, with an average SD of 0.015 in 46,XX and -1.43 in 46,XY. Thelarche and pubarche did not develop properly in some cases despite estradiol treatment.

Conclusion: This study represents the largest cohort of pediatric cases of 17-hydroxylase deficiency (17OHD) documented in the literature. Hypertension and hypokalemia can serve as guiding indicators for early diagnosis.The final height is typically considered to be normal. The relationship between genotype and phenotype remains elusive. The initial genetic test for exon 1-6 deletions may be MLPA in our region.