Congenital myotonia, autosomal recessive form: genes and variants
Congenital myotonia, autosomal recessive form is linked to 1 analyzed protein (CLCN1). 90 DNA variants are known to cause it; 453 more are uncertain, and 19 of those already look disease-causing on computable evidence.
Last updated 2026-09-30. Research information, not medical advice.
Genes linked to Congenital myotonia, autosomal recessive form
CLCN1: Chloride channel protein 1
Its chloride conductance stabilizes the resting membrane potential of skeletal muscle and prevents repetitive firing after contraction. Loss-of-function variants cause myotonia congenita, with delayed muscle relaxation and stiffness.
90 disease-causing and 453 uncertain variants in CLCN1 are linked to Congenital myotonia, autosomal recessive form.
Where Congenital myotonia, autosomal recessive form variants cluster
- CLCN1 Helical (positions 483–498): 7 of 90 disease-causing changes, 4.8× more than its size predicts.
- CLCN1 Helical (positions 281–290): 5 of 90 disease-causing changes, 5.5× more than its size predicts.
- CLCN1 Transmembrane (positions 302–321): 7 of 90 disease-causing changes, 3.8× more than its size predicts.
- CLCN1 Note=Loop between two helices (positions 415–418): 3 of 90 disease-causing changes, 8.2× more than its size predicts.
- CLCN1 Helical (positions 541–554): 5 of 90 disease-causing changes, 3.9× more than its size predicts.
Known disease-causing variants in Congenital myotonia, autosomal recessive form
| Variant | Position | Protein part | Clinical label |
|---|---|---|---|
| CLCN1 A313V | 313 | Transmembrane | Disease-causing (★★★★) |
| CLCN1 A566T | 566 | Helical | Disease-causing (★★★★) |
| CLCN1 A331S | 331 | Extracellular | Disease-causing (★★) |
| CLCN1 G416E | 416 | Note=Loop between two helices | Disease-causing (★★) |
| CLCN1 T550R | 550 | Helical | Disease-causing (★★) |
| CLCN1 T550M | 550 | Helical | Disease-causing (★★) |
| CLCN1 I556N | 556 | Extracellular | Disease-causing (★★) |
| CLCN1 L198V | 198 | Cytoplasmic | Disease-causing (★★) |
| CLCN1 C277R | 277 | Helical | Disease-causing (★★) |
| CLCN1 A313T | 313 | Transmembrane | Disease-causing (★★) |
| CLCN1 M485V | 485 | Helical | Disease-causing (★★) |
| CLCN1 L198P | 198 | Cytoplasmic | Disease-causing (★★) |
| CLCN1 G233S | 233 | Helical | Disease-causing (★★) |
| CLCN1 A298T | 298 | Cytoplasmic | Disease-causing (★★) |
| CLCN1 F306L | 306 | Transmembrane | Disease-causing (★★) |
| CLCN1 T310M | 310 | Transmembrane | Disease-causing (★★) |
| CLCN1 G411C | 411 | Extracellular | Disease-causing (★★) |
| CLCN1 W433R | 433 | Extracellular | Disease-causing (★★) |
| CLCN1 F484L | 484 | Helical | Disease-causing (★★) |
| CLCN1 G491E | 491 | Helical | Disease-causing (★★) |
| CLCN1 G499R | 499 | Extracellular | Disease-causing (★★) |
| CLCN1 I527S | 527 | Helical | Disease-causing (★★) |
| CLCN1 I553F | 553 | Helical | Disease-causing (★★) |
| CLCN1 M560T | 560 | Helical | Disease-causing (★★) |
| CLCN1 L629P | 629 | CBS 1 | Disease-causing (★★) |
| CLCN1 E193K | 193 | Helical | Disease-causing (★★) |
| CLCN1 V229M | 229 | Note=Loop between two helices | Disease-causing (★★) |
| CLCN1 G230E | 230 | Note=Loop between two helices | Disease-causing (★★) |
| CLCN1 G285V | 285 | Helical | Disease-causing (★★) |
| CLCN1 E291K | 291 | Cytoplasmic | Disease-causing (★★) |
| CLCN1 F307S | 307 | Transmembrane | Disease-causing (★★) |
| CLCN1 G355R | 355 | Transmembrane | Disease-causing (★★) |
| CLCN1 G482R | 482 | Note=Loop between two helices | Disease-causing (★★) |
| CLCN1 A493E | 493 | Helical | Disease-causing (★★) |
| CLCN1 A531V | 531 | Helical | Disease-causing (★★) |
| CLCN1 E548K | 548 | Helical | Disease-causing (★★) |
| CLCN1 Q552R | 552 | Helical | Disease-causing (★★) |
| CLCN1 D117G | 117 | Cytoplasmic | Disease-causing (★★) |
| CLCN1 M128V | 128 | Transmembrane | Disease-causing (★★) |
| CLCN1 G188A | 188 | Note=Loop between two helices | Disease-causing (★★) |
| CLCN1 I290M | 290 | Helical | Disease-causing (★★) |
| CLCN1 R496S | 496 | Helical | Disease-causing (★★) |
| CLCN1 G523D | 523 | Helical | Disease-causing (★★) |
| CLCN1 V536L | 536 | Helical | Disease-causing (★★) |
| CLCN1 E724D | 724 | Cytoplasmic | Disease-causing (★★) |
| CLCN1 Y137D | 137 | Transmembrane | Disease-causing (★★) |
| CLCN1 T268M | 268 | Cytoplasmic | Disease-causing (★★) |
| CLCN1 R338Q | 338 | Extracellular | Disease-causing (★★) |
| CLCN1 M646I | 646 | CBS 1 | Disease-causing (★★) |
| CLCN1 L843P | 843 | CBS 2 | Disease-causing (★★) |
| CLCN1 V851M | 851 | CBS 2 | Disease-causing (★★) |
| CLCN1 Q160H | 160 | Transmembrane | Disease-causing (★★) |
| CLCN1 W164R | 164 | Transmembrane | Disease-causing (★★) |
| CLCN1 C254W | 254 | Cytoplasmic | Disease-causing (★★) |
| CLCN1 V273M | 273 | Helical | Disease-causing (★★) |
| CLCN1 R421C | 421 | Helical | Disease-causing (★★) |
| CLCN1 V327I | 327 | Extracellular | Disease-causing (★★) |
| CLCN1 A331T | 331 | Extracellular | Disease-causing (★) |
| CLCN1 G416R | 416 | Note=Loop between two helices | Disease-causing (★) |
| CLCN1 P480L | 480 | Note=Loop between two helices | Disease-causing (★) |
Showing 60 of 90.
Uncertain variants in Congenital myotonia, autosomal recessive form that look disease-causing
| Variant | Position | Protein part | Clinical label | Evidence |
|---|---|---|---|---|
| CLCN1 G355E | 355 | Transmembrane | Conflicting reports (★) | +7: G355R at the same position is pathogenic; seen in 6.6e-06 of gnomAD DNA copies; REVEL 0.995 |
| CLCN1 G482E | 482 | Note=Loop between two helices | Conflicting reports (★) | +7: 6 other pathogenic changes within 3 positions; G482R at the same position is pathogenic; seen in 6.9e-07 of gnomAD DNA copies; REVEL 0.994 |
| CLCN1 A566V | 566 | Helical | Conflicting reports (★) | +7: 2 other pathogenic changes within 3 positions; A566T at the same position is pathogenic; seen in 1.4e-06 of gnomAD DNA copies; REVEL 0.983 |
| CLCN1 G285R | 285 | Helical | Conflicting reports (★) | +7: 4 other pathogenic changes within 3 positions; G285V at the same position is pathogenic; seen in 0 of gnomAD DNA copies; REVEL 0.942 |
| CLCN1 I527T | 527 | Helical | Conflicting reports (★) | +7: I527S at the same position is pathogenic; seen in 0 of gnomAD DNA copies; REVEL 0.960 |
| CLCN1 G650S | 650 | CBS 1 | Uncertain (★★) | +7: 2 other pathogenic changes within 3 positions; G650C at the same position is pathogenic; seen in 0 of gnomAD DNA copies; REVEL 0.970 |
| CLCN1 G188S | 188 | Note=Loop between two helices | Uncertain (★) | +7: 3 other pathogenic changes within 3 positions; G188A at the same position is pathogenic; seen in 6.6e-06 of gnomAD DNA copies; REVEL 0.870 |
| CLCN1 G188D | 188 | Note=Loop between two helices | Uncertain (★★) | +7: 3 other pathogenic changes within 3 positions; G188A at the same position is pathogenic; seen in 0 of gnomAD DNA copies; REVEL 0.913 |
| CLCN1 G270D | 270 | Helical | Uncertain (★★) | +7: 3 other pathogenic changes within 3 positions; G270V at the same position is pathogenic; seen in 1.4e-06 of gnomAD DNA copies; REVEL 0.919 |
| CLCN1 I191T | 191 | Helical | Uncertain (★) | +7: 4 other pathogenic changes within 3 positions; I191F at the same position is pathogenic; seen in 2e-06 of gnomAD DNA copies; REVEL 0.979 |
| CLCN1 A331G | 331 | Extracellular | Uncertain (★★) | +7: 2 other pathogenic changes within 3 positions; A331T at the same position is pathogenic; seen in 6.9e-07 of gnomAD DNA copies; REVEL 0.835 |
| CLCN1 A415P | 415 | Note=Loop between two helices | Conflicting reports (★) | +6: 4 other pathogenic changes within 3 positions; A415V at the same position is pathogenic; REVEL 0.961 |
| CLCN1 G190R | 190 | Helical | Conflicting reports (★) | +6: 4 other pathogenic changes within 3 positions; G190V at the same position is pathogenic; REVEL 0.952 |
| CLCN1 W433S | 433 | Extracellular | Conflicting reports (★) | +6: 2 other pathogenic changes within 3 positions; W433L at the same position is pathogenic; not seen in the gnomAD population database; AlphaMissense 0.99 |
| CLCN1 V536A | 536 | Helical | Conflicting reports (★) | +6: V536L at the same position is pathogenic; REVEL 0.938 |
| CLCN1 R421L | 421 | Helical | Conflicting reports (★) | +6: 2 other pathogenic changes within 3 positions; R421C at the same position is pathogenic; seen in 4.1e-06 of gnomAD DNA copies; REVEL 0.766 |
| CLCN1 R421H | 421 | Helical | Conflicting reports (★) | +6: 2 other pathogenic changes within 3 positions; R421C at the same position is pathogenic; seen in 7.5e-06 of gnomAD DNA copies; REVEL 0.677 |
| CLCN1 N567K | 567 | Helical | Conflicting reports (★) | +6: 2 other pathogenic changes within 3 positions; N567H at the same position is pathogenic; not seen in the gnomAD population database; AlphaMissense 1.00 |
| CLCN1 G499E | 499 | Extracellular | Uncertain (★) | +6: 2 other pathogenic changes within 3 positions; G499R at the same position is pathogenic; not seen in the gnomAD population database; AlphaMissense 0.96 |
Which prediction tools work for Congenital myotonia, autosomal recessive form
How often each tool ranks a disease-causing variant above a harmless one (AUROC × 100).
- REVEL: 99 out of 100 (learned from overlapping clinical labels, so this is optimistic)
- CADD: 99 out of 100
- CATVariant: 99 out of 100 (learned from overlapping clinical labels, so this is optimistic)
- SIFT: 97 out of 100
- PolyPhen-2: 95 out of 100 (learned from overlapping clinical labels, so this is optimistic)
- phyloP: 91 out of 100
Same protein, different disease
- Skeletal muscle channelopathy is also caused by CLCN1 variants; they fall in the same places as the Congenital myotonia, autosomal recessive form variants (11 disease-causing).
Diseases related to Congenital myotonia, autosomal recessive form
- Congenital myotonia, autosomal dominant form, also linked to CLCN1
- Hyperkalemic periodic paralysis, also linked to CLCN1
- Hypokalemic periodic paralysis, also linked to CLCN1
- Skeletal muscle channelopathy, also linked to CLCN1
- Batten-Turner congenital myopathy, also linked to CLCN1
Frequently asked questions
Which genes are linked to Congenital myotonia, autosomal recessive form?
In CATVariant, Congenital myotonia, autosomal recessive form is linked to 1 analyzed protein: CLCN1 (Chloride channel protein 1).
How many genetic variants are linked to Congenital myotonia, autosomal recessive form?
555 variants: 90 are classified as disease-causing (pathogenic or likely pathogenic) in ClinVar and 453 are of uncertain significance or have conflicting reports.
Which uncertain variants in Congenital myotonia, autosomal recessive form look disease-causing?
19 uncertain variants reach the likely-pathogenic range of the ACMG/AMP points scale on computable evidence, for example CLCN1 G355E, CLCN1 G482E, CLCN1 A566V, CLCN1 G285R and CLCN1 I527T. These are leads for expert review, not diagnoses.
Which variant effect predictor works best for Congenital myotonia, autosomal recessive form?
Among tools not trained on clinical labels, CADD separates this disease's known disease-causing variants from harmless ones best (AUROC 0.99, based on 66 disease-causing and 13 harmless variants).
About this data
Variant–disease links come from ClinVar, Open Targets and UniProt, pooled from the latest public CATVariant analysis of each human protein. Evidence scores use the ACMG/AMP Bayesian points scale with computable criteria only (position among known disease variants, rarity in gnomAD, calibrated predictors, deep mutational scanning); there is no family or patient data, so they prioritise variants for expert review and never classify them.
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