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Hypermanganesemia with dystonia, polycythemia, and cirrhosis
(often shortened to HMDPC)
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Reviewed October 2012
What is HMDPC?
Hypermanganesemia with dystonia, polycythemia, and cirrhosis (HMDPC) is an inherited disorder in which excessive amounts of the element manganese accumulate in the body, particularly in the brain, liver, and blood (hypermanganesemia). Signs and symptoms of this condition can appear in childhood (early-onset), typically between ages 2 and 15, or in adulthood (adult-onset).
Manganese accumulates in a region of the brain responsible for the coordination of movement, causing neurological problems that make controlling movement difficult. Most children with the early-onset form of HMDPC experience involuntary tensing of the muscles in the arms and legs (four-limb dystonia), which often leads to a characteristic high-stepping walk described as a "cock-walk gait." Other neurological symptoms in affected children include involuntary trembling (tremor), unusually slow movement (bradykinesia), and slurred speech (dysarthria). The adult-onset form of HMDPC is characterized by a pattern of movement abnormalities known as parkinsonism, which includes bradykinesia, tremor, muscle rigidity, and an inability to hold the body upright and balanced (postural instability).
Affected individuals have an increased number of red blood cells (polycythemia) and low levels of iron stored in the body. Additional features of HMDPC can include an enlarged liver (hepatomegaly), scarring (fibrosis) in the liver, and irreversible liver disease (cirrhosis).
How common is HMDPC?
The prevalence of HMDPC is unknown. A small number of cases have been described in the scientific literature.
What genes are related to HMDPC?
Mutations in the SLC30A10 gene cause HMDPC. This gene provides instructions for making a protein that transports manganese across cell membranes. Manganese is important for many cellular functions, but large amounts are toxic, particularly to brain and liver cells. The SLC30A10 protein is found in the membranes surrounding liver cells and nerve cells in the brain, as well as in the membranes of structures within these cells. The protein protects these cells from high concentrations of manganese by removing manganese when levels become elevated.
Mutations in the SLC30A10 gene impair the transport of manganese out of cells, allowing the element to build up in the brain and liver. Manganese accumulation in the brain leads to the movement problems characteristic of HMDPC. Damage from manganese buildup in the liver leads to liver abnormalities in people with this condition. High levels of manganese help increase the production of red blood cells, so excess amounts of this element also result in polycythemia.
Read more about the SLC30A10 gene.
How do people inherit HMDPC?
This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.
Where can I find information about diagnosis or management of HMDPC?
These resources address the diagnosis or management of HMDPC and may include treatment providers.
To locate a healthcare provider, see How can I find a genetics professional in my area? in the Handbook.
Where can I find additional information about HMDPC?
You may find the following resources about HMDPC helpful. These materials are written for the general public.
You may also be interested in these resources, which are designed for healthcare professionals and researchers.
What other names do people use for HMDPC?
What if I still have specific questions about HMDPC?
Where can I find general information about genetic conditions?
The Handbook provides basic information about genetics in clear language.
These links provide additional genetics resources that may be useful.
What glossary definitions help with understanding HMDPC?
autosomal ; autosomal recessive ; bradykinesia ; cell ; cell membrane ; chronic ; cirrhosis ; dysarthria ; dystonia ; fibrosis ; gait ; gene ; hepatic ; involuntary ; involuntary trembling ; iron ; mutation ; nerve cell ; neurological ; parkinsonism ; prevalence ; protein ; recessive ; red blood cell ; sign ; symptom ; toxic ; tremor
You may find definitions for these and many other terms in the Genetics Home Reference Glossary.
See also Understanding Medical Terminology.
References (4 links)
The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? in the Handbook.