Intellectual characteristics of Prader-Willi syndrome: comparison of genetic subtypes.
In Prader-Willi syndrome, the UPD subtype gives stronger verbal IQ than the deletion subtype, so match your language goals to the genetics report.
01Research in Context
What this study did
The team looked at two genetic forms of Prader-Willi syndrome. One group had a missing piece of chromosome 15. The other group had two copies of mom’s chromosome 15 with no dad copy.
Everyone took the same IQ test. The researchers wanted to see if the genetic type changed how kids scored.
What they found
Kids with the mom-only copy scored nine points higher on verbal IQ. Both groups earned the same scores on puzzles and picture tasks.
In short, words come easier when the problem is UPD, not deletion.
How this fits with other research
Hubert et al. (2007) saw the same pattern in Velo-Cardio-Facial syndrome. Children who inherited the deletion from a parent had lower IQ than kids with a brand-new deletion.
Van Aken et al. (2010) looked at 22q11 deletion and found kids still moved their hands poorly on a tracking game even after matching for IQ. That study shows genes can hurt specific skills, not just overall IQ.
Grindle et al. (2012) tested Williams syndrome and found a visual strength inside a low language profile. Together these papers tell us one rule: check both the genetic subtype and the skill profile before you plan lessons.
Why it matters
If your client has PWS, look up the genetic report. Choose UPD kids for talk-heavy goals like mand training or intraverbal stories. Pick deletion kids for visual tasks first, then layer in words. This small switch can save months of trial and error.
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Open the client’s file, find the genetic subtype, and move the strongest verbal targets to UPD kids first.
02At a glance
03Original abstract
Advances in genetics have led to an increased understanding of the role of the genotype on behavioural functioning. The purpose of the present study was to examine differences in intellectual functioning in individuals with Prader-Willi syndrome (PWS) with a paternal 15q11-q13 deletion versus maternal uniparental disomy (UPD) of chromosome 15. Measures of intelligence and academic achievement were administered to 38 individuals with PWS (24 with deletion and 14 with UPD). The subjects with UPD had significantly higher verbal IQ scores than those with deletion (P< 0.01). The magnitude of the difference in verbal IQ was 9.1 points (69.9 versus 60.8 for UPD and deletion PWS subjects, respectively). Only 17% of subjects with the 15q11-q13 deletion had a verbal IQ > or = 70, while 50% of those with UPD had a verbal IQ > or = 70. Performance IQ scores did not differ between the two PWS genetic subtype groups. This is the first report to document the difference between verbal and performance IQ score patterns among subjects with PWS of the deletion versus the UPD subtype.
Journal of intellectual disability research : JIDR, 2000 · doi:10.1046/j.1365-2788.2000.00250.x