chr11-64751337-G-C
Variant summary
Our verdict is Likely benign. Variant got -5 ACMG points: 0P and 5B. BP4_StrongBS2_Supporting
The NM_005609.4(PYGM):c.1957C>G(p.Leu653Val) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000507 in 1,614,182 control chromosomes in the GnomAD database, including 5 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).
Frequency
Consequence
NM_005609.4 missense
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Likely_benign. Variant got -5 ACMG points.
Transcripts
RefSeq
Ensembl
Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | TSL | MANE | Protein | Appris | UniProt |
---|---|---|---|---|---|---|---|---|---|---|
PYGM | ENST00000164139.4 | c.1957C>G | p.Leu653Val | missense_variant | Exon 16 of 20 | 1 | NM_005609.4 | ENSP00000164139.3 | ||
PYGM | ENST00000377432.7 | c.1693C>G | p.Leu565Val | missense_variant | Exon 14 of 18 | 2 | ENSP00000366650.3 | |||
PYGM | ENST00000462303.1 | n.281C>G | non_coding_transcript_exon_variant | Exon 3 of 3 | 2 |
Frequencies
GnomAD3 genomes AF: 0.000644 AC: 98AN: 152238Hom.: 0 Cov.: 32
GnomAD3 exomes AF: 0.000923 AC: 232AN: 251372Hom.: 3 AF XY: 0.000846 AC XY: 115AN XY: 135896
GnomAD4 exome AF: 0.000493 AC: 720AN: 1461826Hom.: 5 Cov.: 31 AF XY: 0.000458 AC XY: 333AN XY: 727218
GnomAD4 genome AF: 0.000643 AC: 98AN: 152356Hom.: 0 Cov.: 32 AF XY: 0.000564 AC XY: 42AN XY: 74504
ClinVar
Submissions by phenotype
Glycogen storage disease, type V Uncertain:1Benign:3
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This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). Publications were found based on this search. The evidence from the literature, in combination with allele frequency data from public databases where available, was sufficient to rule this variant out of causing disease. Therefore, this variant is classified as benign. -
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not provided Uncertain:1Benign:1
The majority of missense variants in this gene are considered pathogenic (Stenson et al., 2014); In silico analysis, which includes protein predictors and evolutionary conservation, supports that this variant does not alter protein structure/function; This variant is associated with the following publications: (PMID: 25914343) -
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Tip-toe gait Pathogenic:1
Toe Walking has various causes, ranging from idiopathic or habitual reasons to an underlying neuromuscular disease. The most observed form of toe walking is idiopathic toe walking (ITW) - a diagnosis of exclusion. ITW occurs in about 5% of children after their second birthday and is a common problem in pediatric orthopedics. In about 70% of these cases, there is spontaneous remission within six months of the onset of ITW. If the toe walk persists, one can assume the presence of a non-idiopathic form of toe walk (n-ITW). In n-ITW, the causes of the abnormal gait are neurological or myogenic. Differential diagnoses such as infantile cerebral palsy, muscular dystrophy, spinal amyotrophy and hereditary motor-sensory neuropathy as well as rare metabolic disorders of the musculature must be considered (Pomarino et al., 2018). In our clinical ITW consultation, we screen children with n-ITW for a genetic form of tiptoe gait using next generation sequencing for gene variants in 49 genes. These are genes in which gene variants can lead to neuromuscular diseases in which an association with toe-tapping gait has been reported or can be suspected due to patients’ clinical symptoms. To the best of our knowledge, this is the first study in which several patients with toe walking displayed heterozygosity for pathogenic or likely pathogenic PYGM mutations and mild symptoms of the metabolic muscle disease McArdle. The findings of our research are in line with recently published observations in heterozygous family members patients with McArdle disease. We should mention that some of the patients in our cohort harbored heterozygous variants in other genes of our gene panel. However, the numbers in this study were too small to workout any resulting combined genetic effects. It is concluded that genetic conditions can contribute to the development of toe walking. Apparently, even a slight genetic weakening of the muscles can lead to changes to the gait pattern. Future studies must show how the pathomechanism can be explained for the PYGM variants and whether there are new therapeutic approaches to be developed based on this research. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at