Autism, mental retardation, and chromosomal abnormalities.

Doctors looked at four autistic children who also had intellectual disability. Each child had small physical differences like low-set ears or wide-spaced eyes.

The team took blood and checked the chromosomes under a microscope. They found new, never-before-seen changes on chromosomes 3, 5, 16, and 17.

All four kids had big pieces of chromosome missing or moved around. These large structural flaws were brand-new to science in 1986.

The doctors said these flaws might explain both the autism and the low IQ. They urged others to run chromosome tests when autism and ID occur together.

Gaily et al. (1998) later screened the kids with PDDs and found only a large share had chromosome flaws. The low number seems to clash with R et al.'s a large share rate, but the 1998 study used a wider autism spectrum while R et al. only counted kids with clear physical signs.

Estécio et al. (2002) found a large share of 30 Brazilian youths had flaws, and Nader-Grosbois et al. (2012) traced one girl's autism to a tiny 16q23.2 deletion. These later papers extend R et al.'s idea: physical clues plus ID warrant genetic testing.

Cohen et al. (2005) pulled the early cases into a review and built a bedside checklist. The checklist keeps R et al.'s core message alive: look at the body, then test the chromosomes.

When you see a client with both autism and unexplained ID, scan for minor physical anomalies. If you spot them, talk to the family about chromosome testing. The test may reveal a known cause, sharpen prognosis, and guide medical follow-up.