Monarch Disease Ontology term MONDO_0015546 (non-distal monosomy 10q) is a rare chromosomal anomaly syndrome, resulting from a partial deletion of the long arm of chromosome 10, with a highly variable phenotype principally characterized by developmental delays (usually of language and speech), variable cognitive impairment and neurobehavioral abnormalities such as autism spectrum disorders and attention deficit disorder. Macrocephaly and mild dysmorphic features may by associated. Overlap with other syndromes, such as Cowden syndrome, Bannayan-Riley-Ruvalcaba syndrome and juvenile polyposis syndrome has been reported. Also known as: non-distal deletion 10q, non-distal monosomy type 10q, non-telomeric monosomy 10q.