Familial aggregation of quantitative autistic traits in multiplex versus simplex autism

Area of Science:

• Genetics
• Neurodevelopmental Disorders
• Quantitative Psychology

Background:

• Simplex autism (SA) involves one affected individual, while multiplex autism (MA) involves multiple.
• Subclinical autistic traits are noted in relatives of individuals with autism.
• Research suggests potential differences in inheritance modes between SA and MA.

Purpose of the Study:

• To investigate if quantitative autistic traits (QAT) distributions support differential genetic transmission for SA and MA.
• To explore familial aggregation patterns of QAT in SA and MA families.

Main Methods:

• Utilized the Social Responsiveness Scale to measure QAT in children and parents.
• Analyzed familial aggregation of QAT in 80 SA families and 210 MA families.
• Compared QAT distributions in siblings and fathers between SA and MA groups.

Main Results:

• MA brothers showed a distinct pathological shift in QAT distribution compared to SA brothers (P < 0.0001).
• QAT aggregation was observed in fathers of MA individuals but not in females.
• Assortative mating was suggested by spousal correlations, but not concordant elevation.

Conclusions:

• Distinct patterns of QAT manifestation exist among male first-degree relatives for simplex versus multiplex autism.
• Findings align with molecular genetic studies suggesting differential intergenerational transmission for SA and MA.
• Characterizing QAT and endophenotypes in relatives can reduce heterogeneity in autism research.