Early identification of autism in fragile X syndrome: a review.
Fragile X infants need systematic autism screening from birth because early signs are common and the window for help opens fast.
01Research in Context
What this study did
Capio et al. (2013) looked at every paper on autism and fragile X syndrome. They wrote a story-style review. They asked: when does autism first show up in babies with fragile X?
They found no big tracking studies of these babies. Most work started after age two. The team said we need newborn follow-up projects like the ones used for baby brothers and sisters of autistic children.
What they found
The review showed autism signs can appear early in fragile X, but no one watches from birth. Without early data we miss the best window for help.
The authors urged clinics to start infant screening tools such as the Denver-modified CHAT as soon as a fragile X diagnosis is known.
How this fits with other research
Stancliffe et al. (2007) already tested Denver-modified CHAT cut-offs in toddlers with fragile X. They caught 75% of later autism cases versus 50% with the old cut-offs. Capio et al. (2013) extends this call back to infancy.
Jones et al. (1998) counted that 1 in 4 young fragile X boys score above the autism cutoff. Casey et al. (2009) added that even mild autistic traits in fragile X girls predict slower growth. These numbers give M et al. the proof that early tracking is worth the work.
Scott et al. (2026) followed the review’s plea and checked service use. Only half of eligible fragile X babies entered Part C by 12 months. This gap shows the screening plan M et al. asked for is still not routine.
Why it matters
If you assess babies known to have fragile X, add an autism screen at every visit. Use the Denver-modified CHAT or a similar tool starting before age one. Early flags let you start eye-contact games, joint-attention routines, and refer to Part C right away. Catching autism soon in fragile X can lift developmental paths for both boys and girls.
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02At a glance
03Original abstract
Fragile X syndrome (FXS) is the leading genetic cause of autism, accounting for approximately 5% of autism cases with as many as 50% of individuals with FXS meeting DSM-IV-TR criteria for autistic disorder. Both FXS and idiopathic autism (IA) are attributed to genetic causes; however, FXS is an identified single gene disorder whereas autism is a complex disorder with multiple potential causes, some of which have been identified. Studies in IA have focused on the prospective longitudinal examination of infant siblings of children with autism as a target group due to their high risk of developing the disorder. We propose that this same model be applied to the study of infants with FXS. There is a lack of research focusing on the early development of autism within FXS and debate in the literature regarding how to best conceptualise this co-morbidity or whether it should be considered a co-morbid condition at all. Studying the emergence and stability of autism in infants with FXS has multiple benefits such as clarifying the underlying mechanisms of the development of autism in FXS and solidifying similarities and differences between co-morbid FXS with autism and IA. Infant research in both IA and FXS are discussed as well as conclusions and implications for practice and future research.
Journal of intellectual disability research : JIDR, 2013 · doi:10.1111/j.1365-2788.2012.01609.x