<unk> , also known as Kleefstra syndrome, is a rare genetic disorder. Terminal deletions of chromosome<unk>  have been associated with childhood hypotonia, a distinctive facial appearance and developmental disability. The facial features typically described include arched eyebrows, small head circumference, midface hypoplasia, prominent jaw and a pouting lower lip. Individuals with this disease may often have speech impediments, such as speech delays. Other characteristics of this disease include: epilepsy, congenital and urogenetic defects, microcephaly, corpulence, and psychiatric disorders. From analysis of chromosomal breakpoints, as well as gene sequencing in suggestive cases, Kleefstra and colleagues identified EHMT1 as the causative gene. This gene is responsible for producing the protein Histone methyltransferase which functions to alter histones. Ultimately, histone methyltransferases are important in deactivating certain genes, needed for proper growth and development. Moreover, a frameshift, missense, or nonsense error in the coding sequence of EHMT1 can result in this condition in an individual.
9q34 deletion syndrome
13q deletion syndrome
22q11.2 deletion syndrome
Saethre-Chotzen syndrome
Bardet-Biedl syndrome
Goldberg–Shprintzen syndrome
Chromosome 2p16.1-p15 deletion syndrome
Apert syndrome