Coffin-Lowry Syndrome
Coffin-Lowry syndrome (CLS) is a relatively rare (1:50,000-100,000 incidence) sex-linked neurodevelopmental disorder that includes severe intellectual disability, dysmorphic features including facial and digital abnormalities, growth retardation, and skeletal changes. Most cases are sporadic with only 20% to 30% of cases having an additional family member. CLS is caused by variable loss of function mutations in the RPS6KA3 gene that maps to Xp22.2 and codes for the hRSK2 S6 kinase that phosphorylates the transcription factor CREB (cAMP response element binding protein) as well as other nuclear transcription factors. Phosphorylated CREB (pCREB) plays a major role in memory formation in fruit flies and mammals by activating specific genes through epigenetic histone acetylation.