In addition to hearing impairment, syndromic hearing impairment is often accompanied by disorders of urinary, skeletal, muscular, nervous, and ocular systems. Genetic factors have shown to play an important role in the pathogenesis of deafness. Mutations of X-linked genes may cause syndromic hearing impairment. Gene mapping, linkage analysis and next-generation sequencing may facilitate delineation of the pathogenesis of X-linked syndromic hearing impairment. This article reviews recent progress in molecular genetic research on X-linked syndromic hearing impairment, which may shed light for the diagnosis and treatment of these diseases.
Genetic Diseases, X-Linked ; genetics ; Genetic Research ; Hearing Loss ; diagnosis ; genetics ; therapy ; Humans ; Molecular Biology

OBJECTIVETo detect potential mutations of fibrillin-1 (FBN1) gene in a child with Marfan syndrome (MFS) and explore its molecular pathogenesis.

METHODSThe 66 exons of the FBN1 gene were analyzed by direct sequencing. SIFT and PolyPhen-2 were used to predict the structural and functional changes at the protein level.

RESULTSA novel heterozygous mutation c.3998 G>A (p.Cys1333Tyr) was found in exon 32 in the child. The same mutation was not found among his unaffected family members and 683 healthy controls. Multiple sequence alignment showed that this novel mutation was located in a highly conserved region of the FBN1 protein across various species and may induce structural change to a functional domain.

CONCLUSIONThe novel c.3998G>A (p.Cys1333Tyr) mutation of the FBN1 gene probably predisposed the MFS in the child. Above finding has enriched the spectrum of FBN1 mutations.