Mucolipidosis IV (MLIV)
Mucolipidosis IV (MLIV) is an autosomal recessive disorder. MLIV is characterized by severe developmental delay evident by the end of the first year of life. Additional features include corneal clouding, retinal degeneration, achorhydria with elevated gastrin, and half of patients have iron deficiency anemia. About 70% of individuals with mucolipidosis IV are of Ashkenazi Jewish heritage.
Confirmatory diagnostic testing is via molecular genetic testing of MCOLN1, the only gene to date to be associated with mucolipidosis IV. Two specific mutations, c.406-2A>G and g.511_6943del, account for 95% of mutations in individuals of Ashkenazi Jewish heritage. MLIV is a disorder of abnormal lysosomal trafficking, and heterogenous storage bodies are noted throughout the body including the brain and parietal cell in this disease.
Treatment is required in a multi-disciplinary approach, including speech therapy, physical therapy for spasticity and ataxia, anti-epileptic drugs (AED) as needed; topical lubricating eye drops, artificial tears, gels, or ointments for ocular irritation; surgical correction of strabismus; high-contrast black and white materials for those with visual impairment.Assessment of iron deficiency treatment with nutritional supplementation of iron may also be helpful.
The knockout mouse for this disorder was created in 2007 in the Slaugenhaupt lab at Massachusetts General Hospital. (AJHG, November 2007 pp.1070-1083)
