OBJECTIVETo explore the clinical features and genetic mutation in a family affected with non-syndrome X-linked intellectual disability (NS-XLID) using whole exome sequencing (WES).

METHODSMultiplex ligation-dependent probe amplification (MLPA) was applied to screen potential mutations of Fragile X syndrome (FXS). Whole exome sequencing (WES) and Sanger sequencing were screen for pathological mutations.

RESULTSFXS was excluded by MLPA analysis. WES has discovered in the proband an ARX gene mutation c.88G>T, which was confirmed by Sanger sequencing. Combining his clinical phenotype with information from the OMIM database, it was inferred that the ARX mutation probably underlies the NS-XLID in the proband. The same mutation was found in his mother and two uncles but not in his father and sister.

CONCLUSIONWES is capable of revealing the mutation underlying NS-XLID and can facilitate genetic counseling for the affected families.