A novel heterozygous variant in exon 32 of the CHD7 gene (c.6923C>T) in a Syrian family with Kallmann syndrome
Background: Kallmann syndrome (KS) and CHARGE syndrome (CS) are rare heritable disorders in which anosmia and hypogonadotropic hypogonadism co-occur. KS is genetically heterogeneous with at least eight genes being involved in its pathogenesis, whereas CS is caused by autosomal dominant mutations exclusively in CHD7 gene. The majority of CS-cases are sporadic and only few familial cases have been reported. In these families, mosaicism in one parent, as well as parent-to-child transmission of a CHD7 mutation, were described. The aim of the study: To report a paternal transmission of a variant in exon 32 of the CHD7 gene (c.6923C>T) in a familial case originally suggested to be affected by KS. Materials and methods: Five genes associated with KS were analyzed using Sanger sequencing and MLPA in a 17-year-old male. Results: The heterozygous variant leading to a change of amino-acid serine at position 2,308 to leucine was found in father his three children. Conclusion: Overall this report confirms the existence of KS without CS symptoms, caused by a mutation in a gene reported pathogenic only in CS.