Comparison of clinical phenotypes between SMA-LED and CMT2O
Clinical phenotypes of SMA-LED and CMT2O were compared in Table 1. The
two groups of patients showed different onset age (P =0.006), with
more SMA-LED patients (30/63, 47.6%) were born with clinical
manifestations, while more CMT2O patients (7/15, 46.7%) had the disease
onset in infancy (<1 year). Besides, no CMT2O patient had
their disease onset in adulthood compared to 7/63 (11.1%) SMA-LED
patients. Seven out of 73 (9.6%) cases of epilepsy were observed in
SMA-LED patients but none was found in CMT2O patients, although the
result was of no statistical significance (P =0.437). The
distribution pattern of muscle atrophy differed between SMA-LED and
CMT2O patients. Although both groups of patients more commonly presented
distal-dominant lower limb atrophy, none of the CMT2O patients had
proximal-dominant wasting compared to 11/42 (26.2%) SMA-LED patients
(P <0.05). In addition, the distribution of muscle
weakness in lower limbs showed a more significant difference between the
two groups (P <0.001). Interestingly, 39/48 (81.3%)
SMA-LED and 1/16 (6.2%) CMT2O patients showed proximal-dominant lower
limb weakness (P <0.05), respectively, while more CMT2O
patients (13/16, 81.3%) had distal-dominant manifestation compared to
SMA-LED (3/48, 6.2%; P <0.05). Abnormal sensation was
more common in CMT2O than SMA-LED patients (9/16, 56.3% and 1/66, 1.5%
respectively, P <0.001). As for CNS involvement, both
SMA-LED and CMT2O patients had a similar incidence of cognitive
impairment (17/66, 25.8% and 4/16, 25.0%, respectively). ADHD was
observed in 9/66 (13.6%) SMA-LED patients compared to none of the CMT2O
patient, although there was no statistical significance
(P =0.263). Besides, seven out of 34 (20.6%) SMA-LED patients
showed abnormal NCV results, while all CMT2O patients were normal on NCV
(P =0.128).