Pseudo Hurler Polydystrophy (PHP) is a rare genetic disorder that belongs to a group of inherited metabolic diseases known as lysosomal storage disorders. It is characterized by an abnormal accumulation of certain substances inside the body's cells, particularly within the lysosomes – specialized compartments responsible for breaking down waste products.
PHP is caused by mutations in the GNPTAB gene, which provides instructions for producing an enzyme called N-acetylglucosamine-1-phosphotransferase (GlcNAc-PT). GlcNAc-PT is essential for the proper functioning of the lysosomes as it helps transport enzymes to these compartments. However, in individuals with PHP, this enzyme is dysfunctional or insufficiently produced, resulting in the build-up of glycosaminoglycans (GAGs) and other substances in various tissues and organs.
The symptoms of PHP can manifest in infancy or early childhood and worsen over time. These symptoms may vary but commonly include skeletal abnormalities, joint stiffness, developmental delays, coarse facial features, growth impairment, and progressive neurological deterioration. Affected individuals may also experience organ enlargement, heart valve abnormalities, and respiratory complications.
Diagnosis of PHP typically involves a combination of clinical evaluation, specialized tests, and genetic analysis. There is currently no cure for PHP, and treatment options primarily aim to alleviate specific symptoms and manage complications. This may involve physical therapy, orthopedic interventions, medications, and other supportive measures to enhance quality of life.
Due to the progressive nature of the disease, PHP can significantly impact an individual's lifespan and quality of life. Regular monitoring, early intervention, and multidisciplinary care are crucial in optimizing outcomes and managing the complexities associated with this rare genetic disorder.
