Variants in INTS1 cause the gene to work imperfectly and disrupt the formation of the integrator complex, a group of proteins in the body that process some types of genetic messages. All affected individuals have two INTS1 variants, either the same variant or two different ones, and a relationship between the type and location of the INTS1 variants and clinical findings has not been found. Testing of parents and brothers and sisters of affected people is generally recommended to establish that parents have one variant each and to work out if other siblings are affected. Testing siblings of an affected person will also identify brother and sisters with one INTS1 variant who might want to be aware of this when they plan a family.
INTS1