Pontine tegmental cap dysplasia

The cause of pontine tegmental cap dysplasia PTCD is unknown. To date, all reported cases have been sporadic with no family history of the condition. Researchers have suggested different processes that may lead to PTCD including:

• A problem with the movement of cells in the developing brain (neuronal migration)
• A disorder of ciliary proteins, structures that play a vital role in human development and everyday functioning
• Impaired axonal guidance, part of neural development involving how neurons (nerve cells) send axons (nerve fibers) out to reach correct targets

More research is needed for the scientific community to form a consensus on the underlying cause or causes of PTCD.

No underlying genetic cause has currently been identified for pontine tegmental cap dysplasia (PTCD). All cases reported in the medical literature have been sporadic with no previous family history. A deletion of genetic material on chromosome 2 including the NPHP1 gene was identified in one individual with PTCD. Mutations within the NPHP1 gene are associated with a number of similar disorders such as Joubert syndrome. While the authors of the case report of this individual concluded that the deletion was likely causative of PTCD, the lack of a similar deletion identified in other cases has caused other authors to suggest that the deletion might have been an incidental finding and might not be causative of PTCD. Genetic testing of a greater number of individuals with PTCD is needed to identify whether there is an underlying genetic cause.

If there is concern regarding a family history of PTCD, we suggest that you consult with a genetics professional.

Pontine tegmental cap dysplasia (PTCD) is a non-progressive neurological disorder characterized by significant developmental delay, cranial nerve dysfunction, and malformation of the hindbrain. Individuals with PTCD may have a collection of medical and developmental problems including: hearing impairment, ataxia, language and speech disorders, feeding and swallowing difficulties, heart malformations and facial paralysis. The severity of the medical problems varies among patients. Some patients have a good long-term prognosis with normal intelligence and partial speech. The cause of PTCD has not been identified. Treatment is focused on managing the underlying symptoms and may include interventions such as cochlear implantation.

The long-term outlook (prognosis) of pontine tegmental cap dysplasia (PTCD) varies. Language disorders are a constant feature in PTCD and may result in a range of symptoms including complete absence of verbal language, sign language only, and understandable speech with moderate to severe problems in both being able to understand and to express oneself. The neurological outcome of PTCD is also variable, ranging from severe intellectual disability to normal intelligence.