Diagnostic Yield of Chromosomal Microarray Analysis in a Cohort of Patients with Autism Spectrum Disorders from a Highly Consanguineous Population.

Doctors ran a genetic test called chromosomal microarray on children with autism. The families came from a population where cousins often marry, so genes are shared more than usual.

They wanted to see how often the test found missing or extra pieces of chromosome that could explain the child’s autism.

The test spotted a clear genetic change in 27 out of every 100 children. Kids who also had unusual facial features or birth defects were the most likely to carry these changes.

Older cytogenetic screens found problems in only 3–6 % of autistic children (E et al. 1998; M et al. 1999). The new microarray tool lifts the pick-up rate to about one in four, a clear leap forward.

Duerden et al. (2012) saw almost the same 24 % yield in a regular clinic, so the high rate is not just due to cousin marriage. Hutchins et al. (2020) later matched the 22 % figure in Italian girls, showing the result holds across different groups.

Taken together, these studies say: if you run the newer test, you can expect useful answers in roughly one-fifth to one-quarter of autism patients, no matter where they live.

When parents ask, "Why does my child have autism?" you can now offer a data-backed answer. A microarray test gives a clear genetic reason in about one out of four cases, especially when the child shows odd facial features or birth defects. Share this number with families during assessment planning and use it to justify the test to insurance or referral teams.