RNU5B-1 related neurodevelopmental disorder with seizures and joint laxity (MONDO_1060179) is a neurodevelopmental disorder in which the cause of the disease is a variation in RNU5B-1 gene and is characterized by global developmental delay, hypotonia, macrocephaly, failure to thrive, abnormality of the eye, seizures, and joint laxity. Also known as: NEDSJL, neurodevelopmental disorder with seizures and joint laxity.