| A rare X-linked syndromic intellectual disability with characteristics of global development delay, postnatal growth retardation leading to short stature, facial dysmorphism, short hands with tapering fingers and progressive skeletal abnormalities including kyphoscoliosis and pectus carinatum/excavatum. Severe clinical presentation was reported in the first male patients described. Following the wide application of molecular genetic testing, the phenotype is now recognized as very variable. Caused by pathogenic variations in the RPS6KA3 gene (Xp22.2-p22.1), which encodes ribosomal protein S6 kinase alpha-3, a growth-factor-regulated protein kinase. An X-linked dominant disorder, about two-thirds of cases occur de novo. Male offspring inheriting the mutation are affected and female carriers can be unaffected or show milder phenotypes. |
