MRT44 is a rare form of intellectual disability, caused by mutations in the METTL23 gene.  This condition has so far been reported in only three families worldwide.  In one of the families, the condition was characterized by the presence of intellectual disability and dysmorphic features.  The two other families did not report the presence of any dysmorphic features.  

Mutations in the METTL23 gene are responsible for MRT44.  This gene codes for a protein, which has been speculated to function as a methyltransferase and as a transcriptional factor regulator.  Defects in the protein have been postulated to lead to abnormal methylation resulting in disrupted neuronal development via epigenetic and non-epigenetic pathways.