Type | Chromosome | Age of onset (in years) | Early symptoms | Tendon reflexes |
---|---|---|---|---|
HMSN 1: dominant; demyelinating | ||||
1 A | 17 | 5–10 | Distal weakness | Absent |
1 B | 1 | 5–10 | Distal weakness | Absent |
1 C | Unknown | 10–15 | Distal weakness | Reduced |
1D | 10 | 10–15 | Distal weakness | Absent |
X | X | 10–15 | Distal weakness | Absent |
HMSN 2: dominant; axonal | ||||
2 A | 1 | 10 | Distal weakness | Absent |
2 B | 3 | 10–20 | Distal weakness Sensory loss | Absent |
2 C | Unknown | 1st decade | Vocal cord & distal weakness | Absent |
2 D | 7 | 16–30 | Distal weakness | Reduced |
HMSN 3 (Dejerine-Sottas) | 2 years | Severe weakness | Absent | |
HMSN 4: recessive; demyelinating/axonal Involves ethnic groups |