The association of Angelman's syndrome with deletions within 15q11-13.
The inheritance of Angelman's syndrome, a disorder characterised by mental retardation, epilepsy, ataxia, and a happy disposition, is debated because affected sibs occur less frequently than expected with autosomal recessive inheritance. After discovering two unrelated patients with a small deletion of the proximal long arm of chromosome 15, 10 further patients with Angelman's syndrome were reassessed. Five had apparently normal karyotypes, four had a deletion within 15q11-13, and one had a pericentric inversion, inv(15)(p11q13) involving the same chromosomal region. In the latter case, the healthy mother had the same pericentric inversion, indicating that the patient also had a submicroscopic mutation on his other chromosome 15. These data map the Angelman locus to 15q11-13 and suggest that de novo visible deletions (associated with a low recurrence risk) and autosomal recessively inherited cases combine to give an overall sib recurrence risk of less than 25%.
Pembrey
M
M
Institute of Child Health, London.
Fennell
S J
SJ
van den Berghe
J
J
Fitchett
M
M
Summers
D
D
Butler
L
L
Clarke
C
C
Griffiths
M
M
Thompson
E
E
Super
M
M
D001259:Ataxia / Q000235:genetics; D002648:Child; D002872:Chromosome Deletion; D002884:Chromosomes, Human, Pair 15; D004827:Epilepsy / Q000235:genetics; D006801:Humans; D008607:Intellectual Disability / Q000235:genetics*; D007621:Karyotyping; D007845:Laughter; D009069:Movement Disorders / Q000235:genetics*; D013577:Syndrome