ATR-X syndrome is an X-linked mental retardation syndrome characterized by mental retardation, alpha thalassaemia and distinct facial features which include microcephaly, frontal hair upsweep, epicanthic folds, small triangular nose, midface hypoplasia and carp-shaped mouth. Here we report two brothers with clinical features of ATR-X syndrome, in whom a novel missense (C>T) mutation was identified in exon 31 of the ATRX gene.