Monarch Disease Ontology term MONDO_0012914 (chromosome 1q21.1 deletion syndrome) can be described as follows. 1q21.1 microdeletion syndrome is a newly described recurrent deletion syndrome with variable clinical manifestations but without the clinical picture of thrombocytopenia - absent radius (TAR) syndrome. Also known as: 1q21.1 microdeletion syndrome, 1q21.1 recurrent microdeletion (susceptibility locus for neurodevelopmental disorders), Del(1)(q21), chromosome 1q21.1 deletion syndrome, isolated cases, monosomy 1q21.1.