Screening for genomic rearrangements and methylation abnormalities of the 15q11-q13 region in autism spectrum disorders.
BACKGROUND
Maternally derived duplications of the 15q11-q13 region are the most frequently reported chromosomal aberrations in autism spectrum disorders (ASD). Prader-Willi and Angelman syndromes, caused by 15q11-q13 deletions or abnormal methylation of imprinted genes, are also associated with ASD. However, the prevalence of these disorders in ASD is unknown. The aim of this study was to assess the frequency of 15q11-q13 rearrangements in a large sample of patients ascertained for ASD.


METHODS
A total of 522 patients belonging to 430 families were screened for deletions, duplications, and methylation abnormalities involving 15q11-q13 with multiplex ligation-dependent probe amplification (MLPA).


RESULTS
We identified four patients with 15q11-q13 abnormalities: a supernumerary chromosome 15, a paternal interstitial duplication, and two subjects with Angelman syndrome, one with a maternal deletion and the other with a paternal uniparental disomy.


CONCLUSIONS
Our results show that abnormalities of the 15q11-q13 region are a significant cause of ASD, accounting for approximately 1% of cases. Maternal interstitial 15q11-q13 duplications, previously reported to be present in 1% of patients with ASD, were not detected in our sample. Although paternal duplications of chromosome 15 remain phenotypically silent in the majority of patients, they can give rise to developmental delay and ASD in some subjects, suggesting that paternally expressed genes in this region can contribute to ASD, albeit with reduced penetrance compared with maternal duplications. These findings indicate that patients with ASD should be routinely screened for 15q genomic imbalances and methylation abnormalities and that MLPA is a reliable, rapid, and cost-effective method to perform this screening.
Depienne
Christel
C
INSERM U679, AP-HP, Groupe Hospitalier Pitié-Salpêtrière, Paris, France.
Moreno-De-Luca
Daniel
D
Heron
Delphine
D
Bouteiller
Delphine
D
Gennetier
Aurélie
A
Delorme
Richard
R
Chaste
Pauline
P
Siffroi
Jean-Pierre
JP
Chantot-Bastaraud
Sandra
S
Benyahia
Baya
B
Trouillard
Oriane
O
Nygren
Gudrun
G
Kopp
Svenny
S
Johansson
Maria
M
Rastam
Maria
M
Burglen
Lydie
L
Leguern
Eric
E
Verloes
Alain
A
Leboyer
Marion
M
Brice
Alexis
A
Gillberg
Christopher
C
Betancur
Catalina
C
D000293:Adolescent; D000328:Adult; D017204:Angelman Syndrome / Q000235:genetics; D001321:Autistic Disorder / Q000235:genetics*; D002648:Child; D002675:Child, Preschool; D002869:Chromosome Aberrations; D002884:Chromosomes, Human, Pair 15 / Q000235:genetics*; D019175:DNA Methylation / Q000235:genetics*; D005260:Female; D017353:Gene Deletion; D018628:Gene Dosage; D006801:Humans; D008297:Male; D018895:Microsatellite Repeats / Q000235:genetics; D011218:Prader-Willi Syndrome / Q000235:genetics; D024182:Uniparental Disomy