Table 1 Clinical characteristics of the described genetically affected siblings
Patient ID | 2042 | 2043 | 2044 |
|---|---|---|---|
Gender | Female | Female | Female |
Age at examination | 20 years | 18 years | 15 years |
Age at onset | – | 8 months | 4 months |
Initial sign / symptom | Hypertonia and hyperreflexia detected during the sampling session | Floppiness | Floppiness |
Delayed motor development | – | + | + |
Delayed speech | – | + | – |
Epilepsy | – | + | – |
Cognitive impairment | – | – | – |
Degree of motor disability | No functional handicap but signs at examination | Walk with support / unable to run | Walk with support / unable to run |
Muscle wasting (UL & LL) | – | – | – |
UL hypertonia | – | – | – |
UL motor deficit | – | – | – |
UL hyperreflexia | + | + | + |
LL hypertonia | + | + | + |
LL motor deficit | – | Severe | Moderate |
LL hyperreflexia | + | + | + |
Sensory impairment | – | – | – |
Dysarthria | – | + | + |
Ocular cerebellar signs | – | + | + |
Dysmetria | – | – | – |
Optic atrophy | – | – | – |
Clinical summary | Pyramidal features | Pyramidal features, seizures, delayed speech, ocular cerebellar signs and dysarthria | Pyramidal features, ocular cerebellar signs and dysarthria |
MRI changes in brain and spinal cord | + | + | + |
Serum lactate level in mmol/L (reference range 0.5–2.2 mmol/L) | 6.13 | 6.8 | 5.97 |