Mucolipidosis IV Foundation

Welcome to the Mucolipidosis IV Foundation website at ml4.org. We hope you find our web design easy to use and the information helpful.

Typical “Classic” Mucolipidosis Type IV (ML4)

• Psychomotor retardation, similar to cerebral palsy.
• Mental retardation
• Children typically reach a maximum developmental age of 15 months in language and motor function.
• Receptive abilities are better than expressive abilities.
• Hypotonia (low muscle tone), but tendon reflexes are usually spastic.
• Corneal clouding
• Pseudo-strabismus (false appearance of crossed eyes)
• Progressive retinal degeneration, resulting in severe visual impairment/blindness by late teenage years.
• MRI of the brain typically shows a thin corpus collosum, and delayed growth in white matter of brain (myelination)
• Achlorhydria (lack of acid in the stomach)
• Elevated gastrin levels in stomach
• Anemia (iron deficiency)
• Individuals with ML4 typically survive to adulthood, although it is believed that their life expectancy is reduced compared to healthy individuals.

Atypical  and Mild Mucolipidosis Type IV (ML4)

• Individuals with Atypical or Mild ML4 are less severely affected than others with Typical “Classic” ML4.
• Some individuals attain the ability to walk independently. They develop slowly progressive ataxia and have mild eye abnormalities.
• Other individuals have presented with progressive visual impairment while having relatively normal psychomotor development.