PMC

These photographs demonstrate the mild dysmorphic features of the patient, including microcephaly, a triangular and mildly asymmetric face, prominent forehead, slightly downslanting and almond-shaped palpebral fissures, mild ptosis, high nasal bridge and a small chin (panels A and B). He had bilateral 5^th finger clinodactyly (panel C) and bilateral optic nerve hypoplasia (panel D).

Ideogram of chromosomes 16 with the trisomic region highlighted. Examples of genes known to map to these chromosomal segments are noted, according to the information in build 35.1 of the Homo sapiens sequence on the NCBI Map Viewer and Online Mendelian Inheritance in Man. Hypothetical proteins and open reading frames are omitted from the list. In some cases, the exact order of transcripts is ambiguous.

Ideogram of chromosome 13 with the monosomic region highlighted. Examples of genes known to map to these chromosomal segments are noted, according to the information in build 35.1 of the Homo sapiens sequence on the NCBI Map Viewer and Online Mendelian Inheritance in Man. Hypothetical proteins and open reading frames are omitted from the list. In some cases, the exact order of transcripts is ambiguous

Routine cytogenetics identified a translocation of material of unknown origin onto 13q33 (panel A). Using probes specific for subtelomeric sequences, a translocation was identified from 16p (green) onto 13q (panel B, red probe is for 16q). Similarly, two probes for distal 13q (red and green probes, panel C) were absent from one chromosome 13 identified using an aqua-labeled proximal 13q probe. A FISH BAC probe specific for the ZIC2 gene on 13q (panel D, green probe) confirms that it is not deleted in this patient.