• 1: Home
• 2: MPS Diseases
  • 2.1: Overview of symptoms
  • 2.2: Overview of treatment
  • 2.3: Which are the MPS Diseases
    • 2.3.1: MPS I
    • 2.3.2: MPS II
    • 2.3.3: MPS III
    • 2.3.4: MPS IVA
    • 2.3.5: MPS IVB
    • 2.3.6: MPS VI
    • 2.3.7: MPS VII
    • 2.3.8: MPS IX
    • 2.3.9: ML I
    • 2.3.10: ML II and III
    • 2.3.11: ML IV
    • 2.3.12: Fucosidosis
    • 2.3.13: Mannosidosis
    • 2.3.14: Sialic Acid Storage Disease
    • 2.3.15: MSD
    • 2.3.16: AGU
    • 2.3.17: Winchester
    • 2.3.18: Geleo Physic Dysplasia
  • 2.4: Personal stories
• 3: Fabry Disease
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• 30: Terms and Conditions

Mucolipidosis IV (ML IV)

Mucolipidosis IV (ML IV) is a rare genetic disorder belonging to a group of disorders known as the lysosomal disorders. It is most commonly seen in Jews of Eastern European background. Other names for this condition include Ganglioside Sialidase Deficiency and Sialolipidosis.

What causes ML IV?

ML IV is a rare inherited metabolic disorder believed to be caused by alterations in a membrane protein due to mutations in the mucolipin-1 gene. This results in the blockage of endocytic transport which is the absorption of materials, for example, into the cell. This prevents the lysosomes forming correctly which results in a storage of complex lipids within the lysosome. This can cause iron deficiency anaemia and the neurodegenerative features seen in ML IV.

How is ML IV inherited?

ML IV is an autosomal recessive disease; both parents must carry the same defective gene and each pass this same defective gene to their child. Where both parents are carriers of the ML IV gene there is a 25% (1:4) chance of having an affected child with each pregnancy. There is a 50% (1:2) chance of a child receiving only one copy of the defective gene and therefore being a carrier. A carrier will not be affected but can pass the defective gene to his/her offspring. The remaining 25% (1:4) will be neither affected nor a carrier. Using information from an affected individual’s DNA, it may be possible to determine whether brothers and sisters are carriers of, or affected by, ML IV.

All families of affected children should seek further information from their doctor or from a genetic counsellor before planning to have more children. There is a more detailed explanation of this complex subject in a booklet available from the MPS Society on the Pattern of Inheritance in MPS diseases. Please visit our Information Resource section.

Genetic counselling

All parents of children with a lysosomal storage disease should consider asking for genetic counselling before having other children. The counsellor should be able to provide non-directive advice on the risk to close relatives, reproductive choices available and to suggest whether the wider family should be informed.

Further information

There is a detailed fact sheet on ML IV produced by the MPS Society in collaboration with parents and doctors drawing on their experience and with reference to medical literature. The fact sheet includes detailed information on the presentation and clinical management of the disease and treatment options available. Please visit our Information Resource section.