Monarch Disease Ontology entry MONDO_0016911 (partial deletion of the long arm of chromosome 13) can be described as follows. A cytogenetic abnormality that refers to the allelic loss of all or part of the long arm of chromosome 13. Also known as: partial deletion of chromosome 13q, partial deletion of the long arm of chromosome type 13, partial monosomy of chromosome 13q, partial monosomy of the long arm of chromosome 13.