RYR1 and X-linked syndromic intellectual disability: Apart from that of the known molecular marker IDH1, we found that the status of cell division cycle 27 (CDC27), podocon (PODN), α-thalassemia/mental retardation syndrome X-linked (ATRX) and ryanodine receptor type 1 (RYR1) was significantly different between the two subgroups (P<0.05) (Figure 5A).