WES detection and analysis of SMS family

The abnormality of SMS gene could induce X chromosome linked Snyder-Robinson mental retardation syndrome(Mental retardation, X-linked, Snyder-Robinson type, SRS [MIM:309583]). Loss of spermine synthase enzymatic activity causes SRS. Decreased SMS enzyme activity confirms the pathogenicity of an SMS sequence variant. SRS shows variable phenotypes and female carriers are normal.The characteristic features of SRS include asthenic build, facial dysmorphism with a prominent lower lip, kyphoscoliosis, osteoporosis, and speech abnormalities. Developmental delay usually presents as failure to meet early developmental milestones and then evolves to moderate to profound intellectual disability(which appears to remain stable over time) and variable motor disability