Background Congenital adrenal hyperplasia (CAH) is an autosomal
recessive disorder caused by pathogenic variants in seven genes involved
in the cortisol and aldosterone biosynthetic pathway. The second most
common cause, 11 beta-hydroxylase deficiency (11 beta OHD), is
attributed to pathogenic variants in the CYP11B1 gene encoding for the
enzyme 11 beta-hydroxylase (11 beta OH). Case presentation A 13-year-old
girl was referred to the pediatric endocrinologist due to a syncopal
episode. She is the third child of non-consanguineous parents. She
presented with premature adrenarche at the age of 6 years and menarche
at the age of 12 years. On physical examination, her height was 154.5 cm
and weight 50 kg, while she presented with acne, hirsutism,
clitoromegaly, and normal blood pressure. Laboratory investigation
revealed increased androgen levels and poor cortisol response to the
ACTH stimulation test. From the family history, the mother was diagnosed
with CAH at the age of 10 years and was under treatment with
methylprednisolone. Previous molecular investigation of the CYP21A2 gene
was negative. Due to the increased androstenedione levels in the index
patient, the suspicion of 11 beta OH was raised, and she was
investigated for 11-deoxycortisol, 11-deoxycorticosterone, and CYP11B1
gene pathogenic variants. The patient and her mother were found to be
compound heterozygous for two novel variants of the CYP11B1 gene.
Conclusion We present a case of CAH due to compound heterozygosity of
two novel pathogenic variants of the CYP11B1 gene, emphasizing the
importance of molecular investigation in order to confirm clinical
diagnosis and allow proper genetic counseling of the family
