Table 1 Patients harboring the m.15923A > G mutation in the MT-TT gene
From: Mutation m.15923A>G in the MT-TT gene causes mild myopathy – case report of an adult-onset phenotype
Patient 1 | Patient 2 | Patient 3 | Patient 4 | |
|---|---|---|---|---|
Reference | [8] | [10] | present study | |
Age at onset | Day 2 | Childhood | 6 years | 54 years |
Age at the latest examination | Died at the age of 56 h | 19 years | 15 years | 64 years |
Hypoglycemia | yes | – | – | – |
Lactic acidosis | yes | yes | yes | – |
Multisystem failure | yes | – | – | – |
Short stature | – | – | yes | – |
Hearing impairment | – | yes | yes | Age-related |
Exercise intolerance | – | yes | – | yes |
Muscle weakness | – | yes | – | yes |
Generalized seizures | – | yes | yes | – |
Myoclonic seizures | – | yes | yes | – |
Cognitive delay | – | yes | – | – |
Migraine | – | yes | yes | – |
Ataxia | – | yes | – | – |
Dysmetry | – | yes | – | – |
Dysarthria | – | yes | – | – |
Vomiting | – | yes | – | – |
Retinitis pigmentosa | – | yes | yes | – |
Ptosis | – | – | – | yes |
Diplopia | – | – | – | yes |
MRI | – | Cortical and cerebellar atrophy | Basal ganglia calcifications | Nonspecific white matter lesions in frontal lobe |
Family history | Several miscarriages of the mother | Deafness, maternal aunt | Negative | Nonspesific |
RRF | n.a. | yes | yes | yes |
COX-negative | n.a. | yes | yes | yes |
Other | n.a. | Mitochondrial aggregates with abnormal structure | n.a. | Mitochondrial aggregates with abnormal structure |
Functional studies | Decreased activity of complexes III and IV | Complex IV normal | Defect in tRNA modification | COX-negative fibres had higher mutation heteroplasmy than normal fibres |
Heteroplasmy | ||||
Blood | n.a. | 10% | n.a. | < 1%a |
Skeletal muscle | n.a. | 78% | > 95%b | 33% |
Buccal epithelium | n.a. | n.a. | n.a. | 2% |