Each brother presented with intellectual disability and clinical and radiographic features consistent with CLS. qRT-PCR analyses performed on mRNA from the peripheral blood of the three siblings revealed a marked reduction of RPS6KA3 levels suggesting a loss-of-function mechanism.
The Coffin-Lowry syndrome (CLS) is a developmental disorder caused by mutations in the Rsk2 gene and characterized by intellectual disabilities associated with growth retardation.
The loss of RSK2 activity in humans leads to Coffin-Lowry syndrome, which is manifested by mental retardation, growth deficits, skeletal deformations, and psychosis.