Multiplex ligation-dependent probe amplification as a screening test in children with autism spectrum disorders

Autism spectrum disorders (ASDs) are a heterogeneous group of neurodevelopmental disorders, characterized by the presence of various symptoms related to deficits in communication and social interactions as well as stereotyped and repetitive behavior. Increasing evidence indicates the contribution of genetic factors in the etiology of ASDs. Genetic diagnosis in ASDs is based on identifying chromosome aberrations, microaberrations and point mutations in specific genes. One of the diagnostic tools is multiplex ligase-dependent probe amplification (MLPA) with a set of probes dedicated to ASDs (SALSA MLPA P343 Autism-1; MRC-Holland BV, Amsterdam, the Netherlands) targeting the genes located in the regions 15q11-q13, 16p11 and the SHANK3 gene in the 22q13 region.

Our study included 240 patients referred to the clinical genetics unit because of ASDs and/or developmental delay and/or an intellectual disability. Before genetic testing, the patients underwent a comprehensive medical work-up.

Multiplex ligase-dependent probe amplification was performed in 256 DNA samples from 240 probands and 16 family members using the SALSA MLPA P343 Autism-1 probe mix (MRC-Holland BV) according to the manufacturer's protocol.

We obtained 234 normal results and 22 abnormal results (15 probands and 7 abnormal results for probands' parents or siblings). We diagnosed 1 16p11 microdeletion syndrome and 1 16p11 microduplication syndrome. We also found 3 deletions and 1 duplication in 15q13 region including 2 or 3 genes and 9 single probe alterations in the regions examined (1 duplication and 7 deletions).

Due to the low costs, MLPA test may be a good tool for the genetic screening of ASD patients.