2p21 microdeletion syndrome homozygous 2p21 microdeletion syndrome Homozygous deletion of chromosome 2p21, containing two closely located genes, SLC3A1, and PREPL, has been linked to the hypotonia–cystinuria syndrome. Symptoms include generalized hypotonia at birth, failure to thrive, cystinuria, and growth retardation. Orphanet:369886 2p21 contiguous gene deletion syndrome Term added in response to Mondo restructuring. To be considered for replacement or obsoletion in EFO also. UMLS:CN204808