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Table 3 Summary of recurrence risk estimates for prospective parents relative to general population

From: Genetic counseling as preventive intervention: toward individual specification of transgenerational autism risk

Indicator of familial ASD liability

Relative recurrence risk

Source

Mother with ASD-affected sibling*

3

Bai D, et al. [18]

Father with ASD-affected sibling*

2

Mother and father with upper quintile of QATs

1.85

Lyall K, et al. [19])

Either mother or father with upper quintile of QATs

1.52

Mother with ASD-affected sibling* and elevated QATs

[~6.5]**

Second Generation Project

  1. *Idiopathic ASD is assumed. For ASD with a known genetic cause, recurrence will vary based on that variant’s inheritance and penetrance. For example, in Renpenning Syndrome, an X-linked disorder affecting males [54], a sister carrying the associated X-linked mutation has a 50% likelihood of having an affected son, who then has an estimated 38% likelihood of ASD [55].
  2. **This estimate, based on dividing our observed second-generation offspring ASD prevalence (13%) by general population ASD prevalence (~2%), is highly preliminary, given it is derived from a small sample subject to bias from clinical ascertainment of ASD. Nevertheless, it confirms elevated transgenerational ASD risk in parents with two markers of aggregated ASD liability (having an ASD-affected sibling and elevated QATs) and highlights the need for future research in large, genetically informative samples examining joint interactions of predictors of transgenerational ASD risk