Angelman syndrome is a neurodevelopmental disorder characterized by severe
motor and mental retardation, microcephaly,
ataxia, jerky limb movements such as hand flapping,
hyperactivity, seizures, absence of speech, frequent
smiling and outbursts of laughter, and unusual
facial features, characterized by a
large mouth and jaw, an open-mouthed expression,
with a great propensity for protruding the tongue.
Angelman syndrome is caused by the loss of the normal maternal contribution to a region of chromosome 15, most commonly by deletion of a segment of that chromosome. Other causes include uniparental disomy, translocation, or single gene mutation in that region.
Research has shown a mutation of the UBE3A gene can lead to Angelman syndrome. The UBE3A gene is part of the ubiquitin pathway which is present on both the maternal and paternal chromosomes, but differs in the pattern of methylation. The paternal silencing of the UBE3A gene occurs in a brain region-specific manner; in the hippocampus and cerebellum, the maternal allele is almost exclusively the active one. The most common genetic defect leading to Angelman syndrome is a ~4Mb (mega base) maternal deletion in chromosomal region 15q11-13 causing an absence of UBE3A expression in the paternally imprinted brain regions.
Methodology: Sequencing of entire coding region
Purpose: Confirmation of Clinical Diagnosis
ICD-10 code Q93.5
Test Requisition: Sequencing Requisition
CPT Code: 81406 Cost: $1350.00
Turn-around-time: 5-6 weeks
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