Author(s)
J. F. Ha
A. Ahmad
M. Lesperance
Affiliation(s)
University Of Michigan
Abstract:
The advent of chromosome microarray analysis (CMA) for evaluation of patients with multiple congenital anomalies has made it possible to define chromosomal imbalances with greater precision and resolutions significantly smaller than possible by standard G-banded chromosome analysis. We describe two patients with novel chromosomal anomalies involving chromosome 22q13, a locus associated with Phelan-McDermid syndrome (PMS). To characterize the novel phenotypic and genotypic findings of two patients with 22q13 microdeletions, comparing and contrasting with classic features of PMS. Retrospective case reviews Case 1 is a 4-year-old boy with global developmental delay, esotropia, moderate aortic root dilation, genu valgum, and in-toeing gait. MRI Brain for evaluation of neonatal hypotonia revealed a left cerebellopontine angle arachnoid cyst. He referred on newborn hearing screening, and diagnostic ABR showed left profound retrocochlear hearing loss. Surgical intervention was deferred, with spontaneous resolution at two without hearing recovery. CMA revealed a novel, de novo 5.1 Mb microdeletion of 22q13.31q13.33 not involving SHANK3, a gene typically deleted in PMS. In contrast, Case 2 is a 6-year-old girl with features of both PMS. She has a complex chromosomal rearrangement including 5.3 Mb 22q13 microdeletion and de novo 2.1 Mb gain of 22q11. We present a novel deletion of chromosome 22q13 in a patient with multiple congenital anomalies and features distinct from PMS. The presentation of congenital unilateral hearing loss and ipsilateral intracranial cyst posed an interesting management dilemma. Most arachnoid cysts are asymptomatic and do not require intervention, although hearing loss may be considered an indication.