A Rare Cause of Hypergonadotropic Hypogonadism: Transaldolase Deficiency in Two Siblings.

Transaldolase deficiency is a rare inborn autosomal recessive disorder caused by biallelic mutations in the TALDO1 gene. It is characterized by intrauterine growth restriction, dysmorphism, abnormal skin, cytopenia, hepatosplenomegaly, liver cirrhosis, endocrine problems, renal and cardiac abnormalities. We present two siblings of Turkish origin with early-onset form of transaldolase deficiency and hypergonadotropic hypogonadism in both sexes. The girl (index) was followed-up with cryptogenic cirrhosis, leukopenia and thrombocytopenia, skin abnormalities, congenital heart defects, hypercalciuria, nephrolithiasis, proteinuria, chronic kidney disease throughout childhood. She developed hypergonadotropic hypogonadism in adolescence period. Whole exome sequencing due to the multisystemic involvement revealed a previously described homozygous inframe deletion in TALDO1 gene. Her brother was born as a small for gestational age baby and was also followed-up with cryptogenic cirrhosis since his infancy, together with cytopenia, congenital heart defects, bilateral cryptorchidism, short stature, hypercalciuria, proteinuria and chronic kidney disease in childhood. He presented with testicular microlithiasis and hypergonadotropic hypogonadism in adolescence. Sanger sequencing of TALDO1 gene confirmed the presence of the same homozygous deletion with his sister. The mother was found to be a heterozygous carrier for this deletion. We describe two patients with multisystemic involvement since neonatal period who presented with an additional hypergonadotropic hypogonadism in adolescence. The diagnosis of transaldolase deficiency should be kept in mind for these patients, and they must be evaluated for gonadal functions especially during puberty.