Deleterious variants in FRMPD4 have been shown to result in X-linked intellectual developmental disorder-104 (XLID104) (MIM* 300983). The clinical features associated with this disorder include mild to severe intellectual disability, delayed speech and language, delayed gross motor development, tremors, dystonia, hypotonia, spasticity, strabismus, and seizures. Behavioral disturbances such as aggression, opposition, self-injurious behavior, hyperactivity, attention-deficit/hyperactivity disorder (ADHD), and autism spectrum disorder (ASD) have been observed. Approximately 1–3% of the general population are affected by intellectual disability and over 162 XLID genes, including FRMPD4, have been identified. This disorder has an X-linked inheritance pattern and is typically maternally inherited.
FRMPD4