Mucolipidosis IV

Mucolipidosis type IV is an inherited disorder that affects the development of nerves. Approximately 95% of individuals are severely affected, while the remaining 5% have a mild form of Mucolipidosis IV. Symptoms of the disease are not present at birth, but become evident by the end of the first year of life. Most infants with the disease are unable to crawl, sit up, or control hand movements. They also can have difficulty chewing and swallowing due to the muscles of the face moving too slowly. Mucolipidosis IV also affects a child's speech, vision, and ability to learn. In general, individuals with this condition are unable to develop beyond the age of 12 to 15 months. Currently, there is no cure for Mucolipidosis IV, but medical surveillance and care may help to improve some symptoms and overall condition of life. Mucolipidosis IV is expected to shorten one's lifespan, but by how much is unknown. Mucolipidosis IV is caused by pathogenic variants in the MCOLN1 gene.

Mucolipidosis IV is inherited in an autosomal recessive manner. This type of inheritance requires the presence of two copies of a pathogenic variant in the gene for a person to have the genetic disease. Both parents must be carriers of a pathogenic variant in the gene in order to be at risk to have an affected child. The child must inherit a pathogenic variant from each carrier parent in order to be affected. There is a 1 in 4 chance that a baby will inherit two mutated copies of the gene and be affected when both parents are carriers.

There are no signs or symptoms associated with being a carrier for Mucolipidosis IV. However, the risk to have a child affected with the disease is increased. Testing of reproductive partners is recommended for carriers of Mucolipidosis IV.

Mucolipidosis IV is a rare disorder and is estimated to occur in 1 in 40,000 newborns. Most individuals with the disease are of Ashkenazi Jewish heritage.

Genetics Home Reference: Mucolipidosis type IV (http://ghr.nlm.nih.gov/)
Genetic Alliance: Mucolipidosis type IV (http://www.diseaseinfosearch.org/)
Mucolipidosis IV Foundation (http://www.ml4.org/)

OMIM [MUCOLIPIDOSIS IV: 252650] (http://www.ncbi.nlm.nih.gov/omim)
Gene Reviews: Mucolipidosis IV (http://www.ncbi.nlm.nih.gov/books/NBK1116/)

• Full gene sequencing
• Copy number analysis: exons 2 & 6