Table e1: Secondary clinical features for the PERIODIC PARALYSIS algorithm that had to be
excluded as predictors (see Methods). Listed symptoms have significant statistical power to
differentiate between causative genes CACNA1S, KCNJ2 and SCN4A in patients who presented
with paralysis as the chief complaint. However, because not all studies reported on these
symptoms, they were excluded from the prediction algorithm. The sample number fractions
(n/n) indicate how many subjects with a defect in the indicated gene presented with the listed
symptom versus the number of patients who were tested and found positive for the indicated
symptom (e.g., 18 patients had a genetic defect in SCN4A; this constitutes 78.3% versus the
total number of patients who presented with muscular hypertrophy, which was 23). Dashes
indicate zero cases.
Clinical feature
Muscular hypertrophy
EMG myopathy
Permanent muscle
weakness
Muscle atrophy
CACNA1S
(n=103)
-
SCN4A
(n=111)
78.3%
KCNJ2
(n=42)
8.3%
(18/23)
(1/12)
87.5%
83.3%
(7/8)
(5/6)
37.5%
61.7%
(12/32)
(29/47)
75.0%
36.4%
(3/4)
(4/11)
p-value
<0.001
-
<0.001
-
<0.001
-
0.008
Table e2: Secondary clinical features for the MYOTONIA algorithm that had to be excluded as
predictors (see Methods). Compilation of symptoms with significant statistical power (p<0.001)
to distinguish between causative genes CLCN1 and SCN4A in patients who presented with
myotonia as the chief complaint. However, because not all studies reported on these symptoms,
they were excluded from the prediction algorithm. Percentages and fractions as described for
Table e1.
Clinical features
Cold-sensitive myotonia
Percussion myotonia
Muscle atrophy
CLCN1
(n=103)
69.9%
SCN4A
(n=111)
98.9%
(51/73)
(89/90)
93.0%
56.8%
(40/43)
(25/44)
1.1%
22.2%
(3/275)
(4/18)