Molecular genetic and clinical delineation of 22 patients with congenital hypogonadotropic hypogonadism

Background: Congenital hypogonadotropic hypogonadism (CHH) is classified as Kallmann syndrome (KS) with anosmia/hyposmia or normosmic (n) CHH. Here, we investigated the genetic causes and phenotype-genotype correlations in Japanese patients with CHH. Methods: We enrolled 22 Japanese patients with CHH from 21 families (18 patients with KS and 4 with nCHH) and analyzed 27 genes implicated in CHH by next-generation and Sanger sequencing. Results: We detected 12 potentially pathogenic mutations in 11 families, with three having a mutation in ANOS1 (X-linked recessive); three and four having a mutation in FGFR1 and CHD7, respectively (autosomal dominant); and one having two TACR3 mutations (autosomal recessive). Among four patients with KS carrying a CHD7 mutation, one had perceptive deafness and two had a cleft lip/palate. Conclusions: The frequency of CHH genes in the Japanese was compatible with previous reports, except that CHD7 mutations might be more common. Furthermore, partial phenotype-genotype correlations were demonstrated in our cohort.