Table 1.
Summary of clinical features and muscle biopsy findings
| Preterm newborns | Term newborns | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Patient number | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 |
| Clinical data | |||||||||||||||
| Gestational age | 31 w 3 d | 35 w | 30 w | 36 w | 35 w | 36 w | 38 w | 39 w | 39 w | 40 w | 40 w | 37 w 3 d | 38 w | 42 w | 39 w 2 d |
| Age at muscle biopsy (postnatal age) | 20 d | 0 d | 1 m 2 w | 5 d | 19 d | 12 d | 7 d | 4 d | 6 d | 7 d | 17 d | 39 d | 2 m | 1 m 15 d | 3 m 15 d |
| Adjusted age at muscle biopsy | 34 w | 35 w | 36 w | 36 w | 37 w | 37 w | 39 w | 39 w | 40 w | 0 m 7 d | 0 m 15 d | 0 m 21 d | 1 m 15 d | 2 m | 3 m 7 d |
| Age of death | 5 w | 1 d | Alive at 2 y 9 m | 14 d | 20 d | 12 d | 11 d | 12 d | 26 d | Alive at 7 y | Alive at 9 m | 3 m 25 d | 2 m 17 d | Alive at 13 y | 5 m |
| Family history | – | Yes | No | No | No | No | – | Yes | Yes | No | Yes | Yes | No | No | – |
| Miscarriages | Yes | – | No | No | – | – | – | Yes | Yes | No | – | No | Yes | No | No |
| Delivery | Cesarean | Vaginal | Cesarean | Cesarean | Cesarean | – | Vaginal | Cesarean | Vaginal | Cesarean | Cesarean | Vaginal | – | Vaginal | – |
| Position | Cephalic | Pelvic | Pelvic | Pelvic | – | – | cephalic | Pelvic | cephalic | Pelvic | – | Pelvic | – | cephalic | – |
| Reduced fetal movements | Yes | Yes | Yes | No | Yes | – | – | – | Yes | Yes | Yes | Yes | – | Yes | – |
| Polyhydramnios | Yes | Yes | No | No | – | Yes | Yes | No | Yes | No | Yes | No | – | Yes | – |
| Oligohydramnios | No | No | Yes | Yes | – | No | No | No | No | No | No | No | – | No | – |
| Arthogryposis | No | – | No | – | – | – | Yes | No | – | – | No | No | – | No | – |
| Partial limbs retractions | Yes | – | Yes | – | – | – | – | Yes | – | – | Yes | Yes | – | Yes | – |
| Thin ribs | Yes | Yes | – | Yes | No | – | Yes | – | Yes | Yes | – | – | No | – | Yes |
| Respiratory failure | Yes | Yes | Yes | Yes | Yes | – | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| Ventilation assisted | Yes | Yes | Yes | Yes | Yes | – | Yes | Yes | Yes | Yes | Yes | Yes | Yes | No | Yes |
| Hypotonia | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| Wasting muscle | – | Yes | – | Yes | – | Yes | Yes | – | Yes | – | – | Yes | – | Yes | – |
| Facial weakness | No | – | – | Yes | Yes | – | Yes | Yes | – | – | Yes | Yes | Yes | Yes | Yes |
| Swallowing difficulties | – | – | Yes | – | – | – | – | – | – | – | Yes | Yes | – | No | – |
| Weight at birth (g) [SD] | 1700 [+0.2] | 2800 [+0.6] | 1430 [−0.02] | 2560 [−0.5] | – | – | 2065 [−2.4] | 3070 [−0.8] | 2910 [−1.1] | 2860 [−1.5] | 2600 [−2.0] | 3005 [−0.1] | 3580 [+0.5] | 4870 [+2.3] | – |
| Head circumference at birth (cm) [SD] | 31.8 [+1.9] | – | – | 35 [+1.1] | – | – | 32 [−1.4] | 36 [+0.9] | – | 36.5 [+1.1] | 37 [+1.5] | 38.5 [+2.8] | 37.5 [+1.8] | 40 [+3.3] | – |
| Lengtht at birth (cm) [SD] | 43 [+0.8] | – | – | – | – | – | 47.5 [−1.0] | 47 [−1.7] | – | – | 50.5 [−0.5] | 50 [+0.30] | – | 60.5 [+3.5] | – |
| Pyloric stenosis | No | – | Yes | No | – | – | – | – | – | Yes | – | Yes | Yes | – | – |
| Undescended testes | Yes | No | Yes | – | – | – | Yes | – | No | Yes | – | Yes | No | – | Yes + small penis |
| Muscle biopsy | |||||||||||||||
| Biopsied muscle | Vastus lateralis | Vastus lateralis | Vastus lateralis | Vastus lateralis | Deltoid | Deltoid | Vastus lateralis | Deltoid | Deltoid | Deltoid | Deltoid | Vastus lateralis | Vastus lateralis | Deltoid | Vastus lateralis |
| Type 1 fibers (%) | 63 | 46 | 35 | 55 | − | 50 | 42 | 63 | 66 | 57 | 53 | 48 | 62 | 66 | 58 |
| Central nuclei (%) | 80 | 45 | 57 | 69 | 39 | 70 | 84 | 39 | 27 | 44 | 62 | 32 | 31 | 27 | 52 |
| Satellite cells (%) | |||||||||||||||
| By electron microscopy | − | 5.65 | 9.40 | 7.38 | 7.84 | 13.79 | 9.85 | 5.88 | 5.28 | 8.49 | 8.65 | 13.96 | − | − | |
| Confocal, Pax7 | 15.94 | 8.28 | 8 | 4.39 | 10.35 | 14 | 11 | ||||||||
| Myosin | |||||||||||||||
| Slow (%) | 70 | 60 | 44 | 59 | 63 | 54 | 72 | ||||||||
| Neonatal | + | + | + | + | + | + | + | ||||||||
| Developmental | − | − | ± | − | − | − | − | ||||||||
| RYR1 | |||||||||||||||
| Subsarcolemma | + | + | + | + | + | + | + | ||||||||
| Cytoplasma | + | + | + | + | + | + | + | ||||||||
| Perinuclear | ++ | ++ | ++ | ++ | ++ | ++ | ++ | ||||||||
| DHPR | |||||||||||||||
| Cytoplasma | + | + | + | + | + | + | + | ||||||||
| Perinuclear | ++ | ++ | ++ | ++ | ++ | ++ | ++ | ||||||||
| Desmin | |||||||||||||||
| Subsarcolemma | ++ | ++ | ++ | ++ | ++ | ++ | ++ | ||||||||
| Cytoplasma | + | + | + | + | + | + | + | ||||||||
| Perinuclear | ++ | ++ | ++ | ++ | ++ | ++ | ++ | ||||||||
| Vimentin | |||||||||||||||
| Cytoplasma (%) | + | ± | + | ++ | − | ++ | ± | ||||||||
| Caveolin | |||||||||||||||
| Sarcolemma | + | + | + | + | − | + | + | ||||||||
| Cytoplasma | ± | ± | ± | ± | ± | ± | ± | ||||||||
| Disferlin | |||||||||||||||
| Sarcolemma | + | − | + | − | − | − | − | ||||||||
| Cytoplasma | + | + | + | + | + | + | + | ||||||||
d, days; w, weeks; m, months; y, years; RYR1, ryanodine receptor type 1; DHPR, dihydropyridine receptor-a1subunit.
We noted the adjusted-age in “weeks” for the babies aged until 39 weeks of gestation at birth, while for the older babies born at term of 40 weeks or more than 40 weeks of gestation, the adjusted-age was noted in “days” and “months.”