1p36 deletion syndrome confirmed by fluorescencein situhybridization and array-comparative genomic hybridization analysis

Abstract

Pediatric epilepsy can be caused by various conditions, including specific syndromes. 1p36 deletion syndrome is reported in 1 in 5,000–10,000 newborns, and its characteristic clinical features include developmental delay, mental retardation, hypotonia, congenital heart defects, seizure, and facial dysmorphism. However, detection of the terminal deletion in chromosome 1p by conventional G-banded karyotyping is difficult. Here we present a case of epilepsy with profound developmental delay and characteristic phenotypes. A 7-year- and 6-month-old boy experienced afebrile generalized seizure at the age of 5 years and 3 months. He had recurrent febrile seizures since 12 months of age and showed severe global developmental delay, remarkable hypotonia, short stature, and dysmorphic features such as microcephaly; small, low-set ears; dark, straight eyebrows; deep-set eyes; flat nasal bridge; midface hypoplasia; and a small, pointed chin. Previous diagnostic work-up, including conventional chromosomal analysis, revealed no definite causes. However, array-comparative genomic hybridization analysis revealed 1p36 deletion syndrome with a 9.15-Mb copy loss of the 1p36.33-1p36.22 region, and fluorescence in situ hybridization analysis (FISH) confirmed this diagnosis. This case highlights the need to consider detailed chromosomal study for patients with delayed development and epilepsy. Furthermore, 1p36 deletion syndrome should be considered for patients presenting seizure and moderate-to-severe developmental delay, particularly if the patient exhibits dysmorphic features, short stature, and hypotonia.

Detection of submicroscopic chromosomal aberrations by chromosomal microarray analysis for the prenatal diagnosis of central nervous system abnormalities

“…Fetus 8 had a 1p36.33p36.31 deletion, including 50 OMIM genes, that overlapped with the 1p36 deletion syndrome. The 1p36 deletion syndrome is characterized by facial dysmorphism, mental retardation, developmental delay, congenital heart defects, hypotonia, and seizures, 19 but the mother selected to continue pregnancy after genetic counseling. Agenesis of the corpus callosum, a patent ductus arteriosus and foramen ovale, hypotonia, dysmorphic features (including a large anterior fontanel, high forehead, a small nose with a broad base, and low‐set ears) were observed after birth.…”