Mitochondrial DNA depletion syndrome

What it is

A clinically heterogeneous group of mitochondrial disorders characterized by a reduction of the mitochondrial DNA copy number in affected tissues without mutations or rearrangements in the mitochondrial DNA. It is phenotypically heterogeneous, and can affect a specific organ or a combination of organs, with the main presentations described being either hepatocerebral (i.e. hepatic dysfunction, psychomotor delay), myopathic (i.e. hypotonia, muscle weakness, bulbar weakness), encephalomyopathic (i.e. hypotonia, muscle weakness, psychomotor delay) or neurogastrointestinal (i.e gastrointestinal dysmotility, peripheral neuropathy). Additional phenotypes include fatal infantile lactic acidosis with methylmalonic aciduria, spastic ataxia (early-onset spastic ataxia-neuropathy syndrome), and Alpers syndrome.

Key facts

Prevalence

1-9 / 1 000 000 (at birth, Israel)

Age of onset

All ages

Classified as

Category

Prevalence figures describe populations, not individuals, and are often estimates from a single study. Where the figure is an incidence or a birth prevalence, it says so.

Genes reported in subtypes

Orphanet records this gene on 1 more specific entry under this disorder, not on this entry itself:

A well-studied disease is usually split into subtypes, and the gene is curated on whichever one the evidence belongs to. Open a subtype to see which gene goes with it.

Cross-references