Delineation of the cryptic 1qter deletion phenotype.

The 1qter microdeletion is often reported in the literature as a part of a complex chromosome rearrangement. We describe a patient with a normal initial cytogenetic analysis later found by subtelomeric FISH to have a de novo isolated 1qter microdeletion. Further characterization was completed through microarray comparative genomic hybridization (CGH) and specific bacterial artificial chromosomes (BACs) to a region of 5.2-5.3 Mbp. Six additional cases were reviewed from a literature search. While no particular feature is specifically unique, the most frequently associated features include short stature, developmental delay and mental retardation, microcephaly, seizures, abnormal corpus callosum, and abnormal ear shape. This further delineates the phenotype and further narrows the chromosomal region responsible for a 1qter microdeletion phenotype.