Families

What is NEXMIF-encephalopathy?
NEXMIF-E is caused by pathogenic genetic variants in the NEXMIF* gene (also termed NEXMIF-disease causing variants or mutations). The NEXMIFgene is located on the X-chromosome and is important for brain development and function. Mutations in the NEXMIFgene cause development delay, intellectual disability, epilepsy and autism. Males who carry a NEXMIFmutation are all affected. Females can be, either unaffected or affected.
Approximately 90 patients (30 % males) are currently described in the scientific literature.

A more extensive description of the clinical spectrum of NEXMIFmutations can be found in the section “Caregivers – Clinical characteristics.” (link)

Inheritance
NEXMIFis an X-linked gene and therefore males have one copy of the NEXMIFgene and females has two copies. This is why males are all affected and why females can be, either unaffected or affected (depending on whether it is their normal or their mutated gene copy, that is activated).

The NEXMIF-gene mutation can be de novo(i.e., arisen in the individual during very early prenatal development) or inherited from the mother.

*The NEXMIF-gene was previously called the KIAA2022-gene