Clinical Characteristics

The first patient described had developmental delay, severely impaired intellectual development with no speech and refractory generalized tonic-clonic seizures. He displayed repetitive non-purposeful rocking head movements and no toilet control. He had precocious puberty. The second patient had poor overall growth, microcephaly, global developmental delay with poor eye contact. By the age of 13-months, she did not experience any seizures but had tonic posturing. Brain imaging was normal. Dysmorphic features were seen in both patients and include hypoplastic nails and terminal phalanges, small teeth, anteverted nares and earlobes and coarse face.