The PCDH19

Explaining in simple words what PCDH19 syndrome is not easy: we are helped by the Italian[1] association that has been promoting information on the subject and supporting research in this particular field of rare genetic diseases for years. We are talking about a disease that affects about 1 in 1 million people (girls).

PCDH19 is a gene that codes for the protein 'protocadherin 19', which is part of a family of proteins that help connect cells in the central nervous system. If mutated, protocadherin 19 can be malformed, reduced in function, or not produced at all. 

Abnormal expression of protocadherin 19 results in seizures that begin in the first few years of life. Seizures commonly begin around 9 months of age, with most girls having their first episodes by 3 years of age.

These are mainly focal seizures in clusters, often during febrile episodes. This form of epilepsy is almost always drug-resistant. This means that there are no drugs that can be used at home and that consequently hospitalization is almost always necessary.

Epilepsy caused by an abnormality in the PCDH19 gene is associated, but not always, with cognitive deficits of varying degrees, behavioral or relational disorders, and autistic traits.

The mechanism by which PCDH19 mutations lead to this clinical condition is still unknown, and it is also not known at the outset which patients will experience severe epilepsy associated with mental retardation and which patients will have a less severe course.

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For children affected by mutations in the PCDH19 gene, there is currently no cure. 

[1]  https://www.pcdh19research.org/it/home-2/