Submicroscopic subtelomeric deletions of chromosome 9q are associated with a recognizable mental retardation syndrome (Harada et al., 2004; Iwakoshi et al., 2004; Stewart et al., 2004; Neas et al., 2005). Common features in patients with 9q subtelomeric deletion syndrome are severe mental retardation, hypotonia, brachy(micro)cephaly, epileptic seizures, flat face with hypertelorism, synophrys, anteverted nares, everted lower lip, carp mouth with macroglossia, and heart defects.
Genetic Heterogeneity of Kleefstra Syndrome
KLEFS2 (617768) is caused by mutation in the KMT2C gene (606833) on chromosome 7q36. [from
OMIM]