<unk>  (SRS) is an extremely rare inherited genetic disorder characterized by muscular and skeletal abnormalities, varying degrees of intellectual disability, seizures, and slow development. SRS is caused by a mutated SMS gene at chromosome Xp21.3-p22.12, which carries instructions for producing the enzyme spermine synthase. Spermine synthase in turn helps the body produce spermine, a polyamine critical to cell processes such as cell division, tissue repair, and apoptosis. The resulting shortage of spermine in cells causes problems with development and brain function, though the exact mechanism is not understood. The syndrome has also been referred to as<unk><unk>  X-linked mental retardation syndrome (MRXSSR) and spermine synthase deficiency. SRS exclusively affects males. Only about ten families currently have a child with SRS, and 50 people have been diagnosed worldwide since 1969.
Snyder–Robinson syndrome
Cerebral palsy
Nance–Horan syndrome
Prader–Willi syndrome
Shapiro syndrome
Rett syndrome
Zadik–Barak–Levin syndrome
Urban–Rogers–Meyer syndrome