Total submissions: 2
| Submitter | RCV | SCV | Clinical significance | Condition | Last evaluated | Review status | Method | Comment |
|---|---|---|---|---|---|---|---|---|
| Labcorp Genetics |
RCV000819257 | SCV000959907 | pathogenic | Congenital myotonia, autosomal recessive form; Congenital myotonia, autosomal dominant form | 2022-07-29 | criteria provided, single submitter | clinical testing | Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. ClinVar contains an entry for this variant (Variation ID: 661766). For these reasons, this variant has been classified as Pathogenic. This sequence change creates a premature translational stop signal (p.Gln160*) in the CLCN1 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in CLCN1 are known to be pathogenic (PMID: 17932099, 22094069, 23739125). This premature translational stop signal has been observed in individual(s) with myotonia congenita (PMID: 23739125). This variant is not present in population databases (gnomAD no frequency). |
| Practice for Gait Abnormalities, |
RCV003319212 | SCV004023219 | likely pathogenic | Tip-toe gait | 2022-10-10 | no assertion criteria provided | clinical testing | Myopathy refers to diseases that affect skeletal Muscles. These diseases attack muscle fibers, making muscles weak. Inherited myopathies are often caused by inheriting an abnormal gene mutation from a parent that causes the disease. Symptoms of congenital myopathies usually start at birth or in early childhood, but may not appear until the teen years or even later in adulthood. Congenital myopathies are somewhat unique compared with other inherited myopathies, as weakness typically affects all muscles and is often not progressive. Symptoms are: Muscle weakness, most commonly of upper arms and shoulders and thighs, muscle cramps, stiffness and spasms, fatigue with exertion and lack of energy. Our patients all walk on tiptoe, so they show similar symptoms. When we genetically test them with our toe walking panel, we find that around 90 per cent of them have a genetic variant that explains their toe walking. These can be assigned, for example, to the area of myopathies (such as variants of the COL6A3 gene), the area of hereditary neuropathies (such as variants of the KMT2C gene) or the area of metabolic diseases (such as variants of the PYGM gene). In a smaller group of patients with almost identical symptoms, no abnormality is found in the genes of our panel, but spastic paraplegia can be detected. In another small group of our toe walkers, no abnormalities can be detected in the genes analysed in our toe walking panel, nor do they suffer from spastic paraplegia, as is also the case with healthy children. In contrast to these, however, they show a tiptoe gait. These patients suffer from infantile cerebral palsy, in which toe walking can also be observed. |