Mitochondrial DNA depletion syndromes | Period of onset | Clinical features | Genes (aliases) | Chromosomal LOCI | Numbers of mutations | References* |
---|---|---|---|---|---|---|
Hepatocerebral mtDNA depletion syndrome | Neonatal, early childhood | Hepatic dysfunction; psychomotor delay; hypotonia; lactic acidosis; nystagmus; neurological dysfunction | POLG (Polg1/PolgA) | 15q25 | 8 | [10] |
C10orf2 (Twinkle/PEO1) | 10q24 | 3 | [11] | |||
DGUOK (dGK) | 2p13 | 51 | [12] | |||
MPV17 (SYM1) | 2p23.3 | 28 | [13] | |||
 |  |  | TK2 | 16q22-q23.1 | 1 | [14] |
Alpers-Huttenlocher syndrome | Early childhood | Hepatic dysfunction; epilepsia partialis continua; neurological dysfunction | POLG (Polg1/PolgA) | 15q25 | 54 | [15] |
Myopathic mtDNA depletion syndrome | Infancy, early childhood | Hypotonia; muscle weakness; dysarthria and dysphagia; failure to thrive | POLG (Polg1/PolgA) | 15q25 | 1 | [5] |
TK2 | 16q22-q23.1 | 34 | [16] | |||
RRM2B (p53R2) | 8q23.1 | 3 | [5] | |||
 |  |  | DGUOK (dGK) | 2p13 | 1 | [17] |
Encephalomyopathic mtDNA depletion syndrome | Infancy | Hypotonia; muscle weakness; psychomotor delay; sensorineural hearing impairment; lactic acidosis; neurological dysfunction | RRM2B (p53R2) | 8q23.1 | 14 | [18] |
TK2 | 16q22-q23.1 | 1 | [19] | |||
SUCLA2 | 13q12.2 | 9 | [20] | |||
 |  |  | SUCLG1 | 2p11.3 | 13 | [21] |
Mitochondrial neurogastrointestinal encephalomyopathy | Late childhood, adolescence | Gastrointestinal dysmotility; weight loss; peripheral neuropathy;ptosis; neurological dysfunction | TYMP (ECGF1) | 22q13 | 81 | [22] |
RRM2B (p53R2) | 8q23.1 | 2 | [23] | |||
 |  |  | POLG (Polg1/PolgA) | 15q25 | 1 | [24] |