Familial autism and the fragile-X chromosome.
Fragile-X syndrome may underlie some familial clusters of autism—consider genetic referral when multiple family members present with autism plus intellectual disability.
01Research in Context
What this study did
Pear et al. (1984) wrote up two brothers who both had autism and fragile-X syndrome. The paper is a simple case report. It points to fragile-X as a possible genetic cause when autism runs in families.
What they found
Both boys had full autism and the fragile-X mutation. The authors say this match-up is unlikely to be chance. They urge genetic testing when several relatives have autism plus intellectual disability.
How this fits with other research
Jones et al. (1998) later tested 63 fragile-X boys and found 1 in 4 scored above the autism cutoff. The mild-moderate cases looked like the brothers in Pear et al. (1984).
Olsson et al. (2001) went further. They tracked fragile-X boys over time and learned that autistic behavior, not the fragile-X protein level, predicted slower development. This extends the 1984 warning: the behavior profile matters more than the lab number.
Capio et al. (2013) reviewed the field and called for infant studies. They cite the 1984 case as proof we need to watch fragile-X babies early. The message is now systematic screening, not just single reports.
Why it matters
If you see a client with autism plus ID and a family history of the same, think fragile-X. Add a genetic referral checkbox to your intake form. Track social-communication milestones closely in fragile-X clients; the autism features drive the outcome more than the syndrome itself. Early ID lets you start ABA and language therapy sooner, when the brain is most plastic.
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02At a glance
03Original abstract
This report presents two male siblings in whom the diagnosis of infantile autism was found in association with a fragile site on the X chromosome. In addition to their marked autistic characteristics, formal examinations indicated that both boys were severely mentally retarded and had several physical features commonly observed in association with the fragile-X syndrome. The mother of these two siblings also gave birth to identical twin boys, who were developmentally delayed and showed several autistic features prior to their untimely death in a house fire. The possible role of the fragile-X chromosome as an etiological factor in families where there is a clustering of autism and related developmental disturbances is discussed.
Journal of autism and developmental disorders, 1984 · doi:10.1007/BF02409662