Pitt-Hopkins syndrome in a boy with Charcot Marie Tooth disease type 1A: a rare co-occurrence of 2 genetic disorders.

Pitt-Hopkins syndrome is characterized by marked intellectual impairment, hyperventilation episodes, and dysmorphic facial features. This article reports a boy who presented with developmental delay, facial dysmorphism, microcephaly, hypotonia, and areflexia. He was initially diagnosed with Charcot Marie Tooth disease type 1A based on family history and genetic testing. However, severe mental impairment was atypical of Charcot Marie Tooth disease type 1A. Over the next few years he developed characteristic breathing abnormality, hand stereotypies, seizures, and marked constipation. The evolution of these manifestations coupled with the characteristic facial appearance suggested the additional diagnosis of Pitt-Hopkins syndrome, which was confirmed by the genetic defect of the transcription factor 4 on chromosome 18. This case demonstrates the rare co-occurrence of 2 genetic disorders in the same individual.