Intellectual functioning in individuals with Bardet-Biedl syndrome

Area of Science:

• Neuroscience
• Genetics
• Developmental Psychology

Background:

• Bardet-Biedl Syndrome (BBS) is a rare genetic disorder characterized by a wide range of clinical manifestations.
• Intellectual functioning and adaptive skills are known to be affected in BBS, but the extent and specific patterns require further investigation.

Purpose of the Study:

• To investigate intellectual functioning and adaptive skills in individuals diagnosed with Bardet-Biedl Syndrome.
• To explore the influence of vision loss and specific BBS subtypes (BBS1 and BBS10) on cognitive performance.

Main Methods:

• Retrospective analysis of intellectual and adaptive skills assessments (Wechsler scales, ABAS) from 96 participants in the Clinical Registry Investigating Bardet-Biedl Syndrome (CRIBBS).
• Exclusion of legally blind participants and those over 15 from visual-spatial skill analyses to isolate cognitive abilities.
• Comparison of intellectual and adaptive functioning between BBS1 and BBS10 subtypes.

Main Results:

• Mean Full-Scale IQ (FSIQ) was 73.5, with 38.3% scoring 70 or below.
• Females exhibited higher FSIQ and visual intellectual skills than males.
• Nearly 60% had verbal intellectual skills in the low average range or above; individuals with BBS1 showed stronger verbal skills than BBS10, though adaptive functioning was similar.

Conclusions:

• Intellectual functioning deficits are common in BBS, but a broad spectrum of abilities exists.
• Cognitive impairment is not a prerequisite for a BBS diagnosis.
• Lower FSIQ scores are significantly influenced by vision-dependent non-verbal skills, impacting performance even with milder visual impairment.