Is child intelligence associated with parent and sibling intelligence in individuals with developmental disorders? An investigation in youth with 22q11.2 deletion (velo-cardio-facial) syndrome.

The team asked a simple question: Does the IQ of a child with 22q11.2 deletion syndrome track with the IQ of mom, dad, or brothers and sisters?

They gave standard IQ tests to the child, both parents, and any siblings in the house. Then they ran correlations.

IQ scores moved together. When parents or siblings scored higher, the child with 22q11DS usually did too. The link was strong enough to show up in statistics.

Niklasson et al. (2010) mapped the mean IQ in 22q11DS at 71 and flagged visuo-motor gaps. K et al. add the family lens: those gaps partly mirror family IQ.

Van Den Heuvel et al. (2018) followed the same kids for almost three years and saw stable cognitive scores but slipping social skills. The family-IQ picture from K et al. helps explain why some kids stay flat while others slide socially—brighter families may buffer both.

Pilowsky et al. (2007) found no special neuropsych mark in autism siblings once you remove diagnosed cases. K et al. differ: in 22q11DS, even unaffected siblings show IQ similarity, hinting that the deletion does not wipe out familial cognitive patterns.

Before you write goals, grab IQ data from parents and siblings. A quick four-subtest screener is enough. If the family average is low, expect slower skill gain and plan shorter teaching loops. If the family is bright, push harder on academic and social targets—the child can likely go further than the 22q11DS mean.