chromosome 18q deletion syndrome true monosomy 18q 2015-09-28T17:05:53Z ORDO:1600 DOID:0060407 ICD10CM:Q93.5 18q- syndrome elvira disease_ontology OMIM:601808 This chromosomal abnormality is associated with intellectual impairment (moderate-severe), behavioral disorder, epilepsy and dysmorphic features including microcephaly, turricephaly, deep-set-eyes, broad nasal bridge, high arched or cleft palate, carp shaped mouth and small hands and feet. Cardiac defects may occur. Neuroimaging shows abnormal myelination, and may show cerebellar hypoplasia. Seizures are of early onset and seizures with focal autonomic seizures features are common (which may result in cardiac arrhythmia and apnoea). It is notable that this chromosome deletion may include the TCF4 gene, which is mutated in Pitt Hopkins Syndrome. MESH:C536580 deletion 18q chromosomal anomaly