Myotonia permanens

General Information (adopted from Orphanet):

Synonyms, Signs: MYOTONIA CONGENITA, ATYPICAL LARYNGOSPASM, SEVERE NEONATAL EPISODIC, INCLUDED
SNEL, INCLUDED
MYOTONIA CONGENITA, ACETAZOLAMIDE-RESPONSIVE
SODIUM CHANNEL MUSCLE DISEASE
MYOTONIA FLUCTUANS
MYOTONIA PERMANENS
Number of Symptoms 34
OrphanetNr: 99735
OMIM Id: 608390
ICD-10: G71.1
UMLs:
MeSH:
MedDRA:
Snomed:

Prevalence, inheritance and age of onset:

Prevalence: No data available.
Inheritance: Autosomal dominant
[Orphanet]
Age of onset: Childhood
[Orphanet]

Disease classification (adopted from Orphanet):

Parent Diseases: Potassium-aggravated myotonia
 -Rare genetic disease
 -Rare neurologic disease

Symptom Information: Sort by abundance 

1
 (HPO:0000366) Abnormality of the nose Occasional [Orphanet] 56 / 7739
2
 (HPO:0000343) Long philtrum Occasional [Orphanet] 262 / 7739
3
 (HPO:0000286) Epicanthus Occasional [Orphanet] 371 / 7739
4
 (HPO:0000277) Abnormality of the mandible Occasional [Orphanet] 394 / 7739
5
 (HPO:0000470) Short neck Occasional [Orphanet] 345 / 7739
6
 (HPO:0000597) Ophthalmoparesis Occasional [Orphanet] 71 / 7739
7
 (HPO:0001276) Hypertonia Very frequent [Orphanet] 317 / 7739
8
 (HPO:0002015) Dysphagia Occasional [Orphanet] 301 / 7739
9
 (HPO:0001288) Gait disturbance Occasional [Orphanet] 318 / 7739
10
 (HPO:0001387) Joint stiffness Occasional [Orphanet] 322 / 7739
11
 (HPO:0003307) Hyperlordosis Occasional [Orphanet] 122 / 7739
12
 (HPO:0100749) Chest pain Occasional [Orphanet] 92 / 7739
13
 (HPO:0004322) Short stature Occasional [Orphanet] 1232 / 7739
14
 (HPO:0002099) Asthma Occasional [Orphanet] 62 / 7739
15
 (HPO:0001608) Abnormality of the voice Occasional [Orphanet] 126 / 7739
16
 (HPO:0010307) Stridor 19 / 7739
17
 (HPO:0002093) Respiratory insufficiency Occasional [Orphanet] 410 / 7739
18
 (HPO:0003552) Muscle stiffness 23 / 7739
19
 (HPO:0002486) Myotonia Very frequent [Orphanet] 29 / 7739
20
 (HPO:0003457) EMG abnormality Frequent [Orphanet] 78 / 7739
21
 (HPO:0003712) Skeletal muscle hypertrophy Occasional [Orphanet] 42 / 7739
22
 (HPO:0003326) Myalgia Occasional [Orphanet] 143 / 7739
23
 (HPO:0001324) Muscle weakness Occasional [Orphanet] 859 / 7739
24
 (HPO:0003202) Skeletal muscle atrophy Occasional [Orphanet] 281 / 7739
25
 (HPO:0003394) Muscle cramps Very frequent [Orphanet] 106 / 7739
26
 (OMIM) Muscle weakness usually does not occur 4 / 7739
27
 (OMIM) Myotonia, potassium-sensitive (may be responsive to acetazolamide) 4 / 7739
28
 (HPO:0012758) Neurodevelopmental delay Occasional [Orphanet] 949 / 7739
29
 (OMIM) Cold sensitivity has been reported 4 / 7739
30
 (OMIM) Laryngospasm, neonatal 4 / 7739
31
 (OMIM) Apnea, episodic, neonatal 6 / 7739
32
 (HPO:0030089) Abnormal muscle fiber protein expression Frequent [Orphanet] 64 / 7739
33
 (OMIM) Serum creatine kinase may be increased 6 / 7739
34
 (OMIM) EMG in myotonia permanens shows continuous myotonic activity 4 / 7739

Associated genes:

ClinVar (via SNiPA)

Gene symbol Variation Clinical significance Reference

Additional Information:

Description: (OMIM) In a report on the 37th ENMC Workshop, Rudel and Lehmann-Horn (1997) stated that the sodium channelopathies can be divided into 3 different forms: paramyotonia, potassium-aggravated myotonia, and periodic paralysis. Potassium-aggravated myotonia includes mild myotonia fluctuans, severe myotonia ...
Diagnosis OMIM Among 22 patients with PMC, 14 with sodium channel myotonia, and 18 myotonia patients with mutations in the CLCN1 gene (118425), Fournier et al. (2006) found that cold temperature was able to exaggerate electromyographic findings in a way ...
Clinical Description OMIM Trudell et al. (1987) reported 14 patients from a kindred with an autosomal dominant form of myotonia characterized by painful muscle stiffness that was provoked by fasting and oral potassium administration. Acetazolamide treatment was effective.

Lerche ...
Molecular genetics OMIM Lerche et al. (1993) identified a heterozygous mutations in the same codon of the SCN4A gene (G1306V; 603967.0007, G1306A; 603967.0012, and G1306E; 603967.0025) in patients with exercise and potassium-aggravated myotonia, myotonia fluctuans, and myotonia permanens, respectively. Patch-clamp recordings ...