Genetic testing in infantile spasms identifies a chromosome 13q deletion and retinoblastoma.
BACKGROUND
Infantile spasms is an epileptic encephalopathy and the common final manifestation of numerous disparate insults to the developing brain during infancy. The varied etiologies may be structural, metabolic, genetic, or unknown. Etiological diagnosis is important as it may lead to specific therapy, which may affect developmental outcome.


METHODS
We report a case of infantile spasms of unknown etiology with dysmorphic features, in which genetic copy number variation microarray testing was included in the investigation of the cause of the disease.


RESULTS
A large deletion of chromosome 13 was identified in the region 13q13 to 13q21.3 encompassing the retinoblastoma gene (13q14.2). Urgent ophthalmological evaluation revealed an asymptomatic retinoblastoma of the left eye, leading to early treatment.


CONCLUSIONS
This is the first case report of infantile spasms specifically associated with a chromosome 13q deletion. Chromosomal region 13q13 to 13q21.3 may contain one or more genes whose hemizygous loss leads to infantile spasms. Copy number variation testing for cryptogenic infantile spasms led to the discovery of a mutation responsible for retinoblastoma, enabling early diagnosis and treatment of a potentially life-threatening cancer. High-sensitivity molecular diagnosis improves health care and substantially reduces expenses. This shift in diagnostic evaluation is broadly relevant to health care.
Division of Neurology, Department of Pediatrics, The Hospital for Sick Children, Toronto, Ontario, Canada. Electronic address: kevin.jones@sickkids.ca.
Kevin
K
Jones
Division of Neurology, Department of Pediatrics, The Hospital for Sick Children, Toronto, Ontario, Canada.
Berge A
BA
Minassian
D002872:Chromosome Deletion; D025063:Chromosome Disorders / Q000150:complications* / Q000235:genetics*; D002882:Chromosomes, Human, Pair 13 / Q000235:genetics; D056915:DNA Copy Number Variations; D042241:Early Diagnosis; D016161:Genes, Retinoblastoma; D005820:Genetic Testing; D006801:Humans; D007223:Infant; D008297:Male; D012175:Retinoblastoma / Q000150:complications* / Q000235:genetics* / Q000628:therapy; D013036:Spasms, Infantile / Q000150:complications* / Q000235:genetics*
chromosome 13q deletion; genetic testing; infantile spasms; retinoblastoma