Parents

The neurodevelopmental disorder with hypotonia, impaired speech, and behavioural abnormalities due to germline mutations in the GNAI1 gene represents a rare, early-onset disease with a non-specific clinical manifestation.

Prevalence
The GNAI1¬-related neurodevelopmental disorder is a rare condition. Its worldwide, or population-specific prevalence is unknown. Only several tens of affected individuals carrying recurrent or unique germline GNAI1 mutations have been described in the literature so far.

Inheritance
Almost all reported cases have virtually a de novo origin as their non-carrier parents are unaffected. To date, only one case of inherited causative mutation has been reported due to the maternal somatic mosaicism (< 10%), e.g. a presence of the mutation in a small proportion of cells of tested tissue (her phenotype is unknown).
In general, parental mosaicism (a presence of mutations in a certain proportion of cells of tested tissues) should not be excluded, as it may represent a recurrence risk in any subsequent pregnancies. The estimation of the recurrent appearance for de novo mutations is commonly reported as < 1%.