Table 3. Clinical manifestations of 11 individuals with genetic variants detected by targeted NGS.
| Characteristics | Patients | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| case 2 | case 5 | case 6 | case 7 | case 9 | case 13 | case 15 | case 17 | case 18 | case 19 | case 20 | |
| Age at study, (years) | 17 | 43 | 16 | 43 | 23 | 39 | 56 | 15 | 26 | 32 | 20 |
| Sex | Female | Male | Male | Male | Female | Male | Male | Male | Male | Female | Male |
| Age at onset, (years) | 6 | 30 | 10 | 27 | 21 | 36 | 41 | 10 | 11 | 29 | 10 |
| Inheritance | D | D | D | D | D | D | D | D | D | D | D |
| Variants | MFN2 | MFN2 | GJB1 | YARS | GJB1 | HSPB8 | GJB1 | GJB1 | GJB1 | GJB1 | BSCL2 |
| Nucleotide | 379G>A | 839G>A | 491G>A | 877G>A | 469T>C | 423G>C | 490C>T | 548G>A | 490C>T | 271G>A | 269C>T |
| Amino acid | G127S | R280H | R164Q | V293M | Y157H | K141N | R164W | R183H | R164W | V91M | S90L |
| Novel or known | Novel | Known | Known | Novel | Novel | Known | Known | Known | Known | Known | Known |
| Muscle weakness UL | Yes | Not | Not | Not | Not | Not | Yes | Yes | Yes | Yes | Not |
| Muscle weakness LL | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| Muscle atrophy UL | Yes | Not | Not | Not | Not | Not | Not | Yes | Yes | Yes | Not |
| Muscle atrophy LL | Yes | Yes | Yes | Yes | Not | Yes | Not | Yes | Yes | Yes | Not |
| Ankle DTRs | Reduced | Absent | Absent | Absent | Absent | Absent | Absent | Absent | Absent | Absent | Reduced |
| Median nerve, R/L | |||||||||||
| cMAP, mV | 1.1/NA | NA/NA | 0.2/1.7 | 0.6/1.4 | 5.8/3.7 | 6.7/NA | 0.9/NA | 12.1/8.1 | NA/NA | 1.2/2.7 | 1.5/NA |
| MNCV, m/s | 37.8/NA | NA/NA | 32.0/34.4 | 27.8/31.9 | 46.0/42.3 | 56.0/NA | 35.3/NA | 40.8/38.8 | NA/NA | 40.7/40.4 | 61.5/NA |
| Peroneal nerve, R/L | |||||||||||
| cMAP, mV | NP/NA | 1.2/5.3 | NP/NA | NP/NA | 0.1/NA | 1.4/NA | NP/NA | 1.9/2.2 | NA/NA | NA/NA | 3.0/2.2 |
| MNCV, m/s | NP/NA | 35.1/37.8 | NP/NA | NP/NA | 34.9/NA | 40.8/NA | NP/NA | 40.7/40.9 | NA/NA | NP/NA | 36.5/37.4 |
| Median nerve, R/L | |||||||||||
| SNAP, uv | 14/NA | NA/NA | 3.8/0.7 | NP/NP | 1.6/3.6 | 25/NA | 5.4/NA | 0.84/1.3 | NA/NA | 9.5/8.7 | 13.2/NA |
| SNCV, m/s | 50/NA | NA/NA | 39.4/34.6 | NP/NP | 44.4/43.1 | 56.5/NA | 37.8/NA | 36.6/40.7 | NA/NA | 44.8/44.8 | 50/NA |
| Sural nerve, R/L | |||||||||||
| SNAP, uv | 1.4/NP | NA/NA | NP/NP | NP/NP | NP/NP | NA/19 | 3.7/4.0 | 3.9/5.0 | NA/NA | 4.8/NA | 23.1/16.6 |
| SNCV, m/s | 26.3/NP | NA/NA | NP/NP | NP/NP | NP/NP | NA/46.8 | 36.2/38.3 | 36.8/36.5 | NA/NA | 36.7/NA | 41/40 |
| Laboratory test | |||||||||||
| CK, U/L | NA | NA | 290 | NA | 212 | 744 | NA | NA | NA | 200 | NA |
| LDH, U/L | NA | NA | 227 | NA | 242 | 255 | NA | NA | NA | 172 | NA |
Abbreviations: D = dominant; NA = not available; NP = not potential; MNCV = motor nerve conduction velocity; cMAP = compound muscle action potential; SNAP = sensory nerve action potential; SNCV = sensory nerve conduction velocity; R/L = right/left.
Normal values: median MNCV ≥ 49 m/s; median cMAP ≥ 4.5 mv; peroneal MNCV ≥ 40 m/s; peroneal cMAP ≥ 2.5 mv; median SNCV ≥ 50 m/s; median SMAP ≥ 5.0 uv; sural SNCV ≥ 40 m/s; sural SMAP ≥ 5.0 uv.
Reference range: CK < 174 U/L; LDH < 211 U/L.