Type II Mucolipidosis, also known as I-cell disease, is a rare inherited metabolic disorder characterized by the impaired functioning of lysosomes within cells. It is classified as a mucolipidosis, a subgroup of lysosomal storage diseases that involve the accumulation of substances within the lysosomes of cells.
Individuals with Type II Mucolipidosis have a deficiency of the enzyme N-acetylglucosamine-1-phosphotransferase (GNPTAB), which is responsible for marking certain proteins with a molecular identifier that directs them to the lysosomes for processing. Without this enzyme, the proteins are not properly targeted and are instead secreted outside the cells, leading to a deficiency of vital enzymes within the lysosomes and subsequent cellular dysfunction.
The symptoms of Type II Mucolipidosis typically present in early childhood and may include developmental delays, skeletal abnormalities, facial dysmorphism, coarse facial features, short stature, and intellectual disabilities. Additional signs may include joint stiffness, hepatosplenomegaly (enlarged liver and spleen), impaired motor skills, and cardiac abnormalities.
Type II Mucolipidosis is inherited in an autosomal recessive manner, meaning that an affected individual must inherit two mutated copies of the GNPTAB gene, one from each parent, in order to develop the condition. Genetic testing can confirm a diagnosis.
As of now, there is no known cure for Type II Mucolipidosis. Treatment is focused on managing the symptoms and improving quality of life. It may involve physical and occupational therapies, medications to alleviate specific symptoms, and supportive care from a multidisciplinary team of healthcare professionals. Research and advancements in genetic therapies provide hope for potential future treatments.
