A 5yearold boy with intellectual disability is referred for genetic evaluation. Family history reveals that his mother has a 30yearold maternal uncle whom she describes as "slow." Which of the following questions about the uncle should the genetic counselor ask FIRST to help assess the relevance of this history?
A. "Where does he work?"
B. "Does he look different from other family members?"
C. "Does he have any children?"
D. "How old was he when he said his first words?"