MONDO_0014273 (microcephaly-thin corpus callosum-intellectual disability syndrome) is a rare, genetic, syndromic intellectual disability disease characterized by progressive postnatal microcephaly and global developmental delay, as well as moderate to profound intellectual disability, difficulty or inability to walk, pyramidal signs (including spasticity, hyperreflexia and extensor plantar response) and thin corpus callosum revealed by brain imaging. Ophthalmologic signs (including nystagmus, strabismus and abnormal retinal pigmentation), foot deformity and genital anomalies may also be associated. Also known as: intellectual developmental disorder, autosomal recessive 40, intellectual disability, autosomal recessive type 40, mental retardation, autosomal recessive type 40.