partial deletion of chromosome 8 partial deletion of the long arm of chromosome 8 8q deletion 8q monosomy Chromosome 8q deletion is a chromosome abnormality that occurs when there is a missing copy of the genetic material located on the long arm (q) of chromosome 8. The severity of the condition and the signs and symptoms depend on the size and location of the deletion and which genes are involved. Features that often occur in people with chromosome 8q deletion include developmental delay, intellectual disability, behavioral problems, and distinctive facial features. Most cases are not inherited, but people can pass the deletion on to their children. Treatment is based on the signs and symptoms present in each person. GARD:0003770 ICD10:Q93.5 MESH:C537828 MONDO:0016907 Orphanet:262065 UMLS:C0795828 chromosome 8q deletion deletion 8q monosomy 8q partial deletion of chromosome 8q partial deletion of the long arm of chromosome type 8 partial monosomy 8q partial monosomy of chromosome 8q partial monosomy of the long arm of chromosome 8