SNP Shot: Genomic Insights

MPV17-related hepatocerebral mitochondrial DNA depletion syndrome is a genetic condition affecting the liver and brain, usually beginning in infancy. Common symptoms include vomiting, diarrhea, failure to thrive, lactic acidosis (a buildup of lactic acid), and hypoglycemia (low blood sugar). Liver problems develop rapidly, leading to liver failure. The liver may be enlarged (hepatomegaly), and bile production is often impaired (cholestasis). In rare cases, liver cancer can occur. Neurological issues, such as developmental delays, weak muscle tone (hypotonia), and reduced sensation in the limbs (peripheral neuropathy), typically follow the liver disease. Sadly, most individuals with this syndrome do not survive beyond infancy or early childhood.

This syndrome is particularly prevalent among the Navajo population of the southwestern United States, where it's known as Navajo neurohepatopathy. Individuals with Navajo neurohepatopathy generally have a longer lifespan than those with MPV17-related hepatocerebral mitochondrial DNA depletion syndrome. Aside from the symptoms mentioned earlier, they may also experience a decreased ability to feel pain, leading to bone fractures without pain and self-mutilation of fingers or toes. Furthermore, they can have corneal anesthesia (lack of sensation in the cornea), potentially causing corneal ulcers and scarring, which impairs vision. The reason for these additional symptoms in Navajo neurohepatopathy is currently unknown.

Inheritance:

The inheritance pattern is autosomal recessive. This means that both parents must carry a copy of the mutated gene, although they themselves typically do not exhibit symptoms of the condition, for their child to be affected.