MMADHC and Global developmental delay: There are a total of 8 genes within the deleted intervals (chr2:147,953,313-152,061,251) in our case (Figure 3A), including three classified as known disease-causing genes listed in the OMIM: MBD5, ORC4, and MMADHC. MBD5 is an important gene within the 2q23.1 region that was believed to be responsible for ASD, intellectual disabilities, developmental delays and seizures in 2q23.1 deletion because point mutations in MBD5 shared the key neurological features with 2q23.1 deletion (Tab1e2)[20,22-24].