What is Mucolipidosis IV?
Mucolipidosis IV is a rare inherited condition that affects the development of the nerves. In about 15% of cases, it also causes existing nerves to degenerate. Most infants with the condition are unable to sit up, crawl, or control their hand motions. They also chew and swallow very slowly, because the muscles of their mouth and face move slowly or not at all.
Children with the condition never learn to walk independently, although a few have learned to use a walker. When they are able to speak, they tend to do so either very slowly or very quickly and slur words, mumble, or whisper. In addition, they rarely learn more than a few words, although some children with mucolipidosis IV have learned to communicate with a few dozen basic signs. In general, people with the disease only reach a developmental age of 12 to 15 months.
Mucolipidosis IV leads to poor vision caused by cloudy corneas (the clear front part of the eye) and degeneration of the retina (the part inside the eye which translates light into images). People with the disease are also prone to dry, irritated eyes, crossed eyes, and pupils that respond slowly to changes in light levels. Although infants with the condition may be born with nearly normal vision, their vision almost always starts to deteriorate by the age of 5. Virtually everyone with the condition is severely visually impaired by the early teens.
About 5% of people with the condition have an atypical variation with less severe movement and vision problems.
How common is Mucolipidosis IV?
Fewer than 100 cases of mucolipidosis IV have been reported in medical literature. More than 80% of those affected are of Ashkenazi Jewish background, and the disease is rare outside this population. Roughly 1 in 100 Ashkenazi Jews is a carrier.
How is Mucolipidosis IV treated?
Treatment for mucolipidosis IV focuses on ensuring comfort and improving function. Physical therapy, foot and ankle orthotics, walkers, and wheelchairs can help maximize mobility. Speech therapy may improve the ability to communicate. Younger children frequently develop eye irritation, which lubricating eye drops, gels, or ointments can soothe.
What is the prognosis for a person with Mucolipidosis IV?
Mucolipidosis IV typically shortens one's lifespan, but people with the disease commonly reach adulthood and some are known to be alive in their mid-40s.