PMC10348358_01
The electrocardiogram showed inverted U waves (A), and the echocardiogram showed no apparent abnormality (B). Genetic analysis using sequencing chromatograms identified a heterozygous KCNJ2 gene variant (c.220A>G; p.T74A) (C). There was no noticeable abnormality in cranial magnetic resonance imaging (D-F).
fneur-14-1170693-g001.jpg
PMC10348358_01_fneur-14-1170693-g001.jpg
fig1
The electrocardiogram of our patient showed a U-wave inversion (Figure 1), and the 24-h dynamic electrocardiogram showed 245 premature ventricular contractions (PVCs) in a total of 91,847 heartbeats. This mutation resulted in the substitution of alanine with threonine at amino acid 74 (p.T74A) (Figure 1), which was reported to be a pathogenic mutation for ATS.
Long-term exercise test results demonstrated that the CMAP amplitude of the right little finger abductor muscle was 74.4% lower than it was at baseline, and the area was reduced by 66% (A,E,I). The median nerve (B), the ulnar nerve (F), and the peroneal nerve (J), and motor conduction were normal. Sensory conduction of the median nerve (C), the ulnar nerve (G), and the superficial peroneal nerve (K) was normal. Electrophysiologic concentric needle examination fibrillation and a sharp positive wave at resting potentials (D). Light contraction showed a narrow waveform (H,L).
fneur-14-1170693-g002.jpg
PMC10348358_01_fneur-14-1170693-g002.jpg
fig2
A long-term exercise test indicated a significant decrease in the compound muscle action potential (CMAP) amplitude of the right little finger abductor muscle, measuring 74.4% lower than the baseline and a 66% reduction in the area (Figure 2).
Short stature, facial features (AP and lateral), low-set ears, hypoplastic mandible, small hands and feet, clinodactyly of the fifth toe, and skeletal anomalies of the patient with ATS (permission was granted by the patient).
fneur-14-1170693-g003.jpg
PMC10348358_01_fneur-14-1170693-g003.jpg
fig3
ATS given the patient's characteristic physical features, including short stature, small hands and feet, clinodactyly of the fifth toe, hypoplastic mandible, and low-set ears (Figure 3). An electrocardiogram revealed slightly inverted U waves.