rs138745073
Variant summary
Our verdict is Uncertain significance. The variant received 3 ACMG points: 3P and 0B. PP3_ModeratePP5
The NM_017739.4(POMGNT1):āc.1010T>Cā(p.Ile337Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000446 in 1,614,084 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. I337V) has been classified as Uncertain significance.
Frequency
Consequence
NM_017739.4 missense
Scores
Clinical Significance
Conservation
Publications
Genome browser will be placed here
ACMG classification
Our verdict: Uncertain_significance. The variant received 3 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes AF: 0.00000657 AC: 1AN: 152204Hom.: 0 Cov.: 33 show subpopulations
GnomAD2 exomes AF: 0.0000239 AC: 6AN: 251316 AF XY: 0.0000147 show subpopulations
GnomAD4 exome AF: 0.0000486 AC: 71AN: 1461880Hom.: 0 Cov.: 90 AF XY: 0.0000523 AC XY: 38AN XY: 727238 show subpopulations
Age Distribution
GnomAD4 genome AF: 0.00000657 AC: 1AN: 152204Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0AN XY: 74356 show subpopulations
ClinVar
Submissions by phenotype
not provided Uncertain:3
- -
- -
Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Has not been previously published as pathogenic or benign to our knowledge; This variant is associated with the following publications: (PMID: 24282183, 30564623) -
Muscular dystrophy-dystroglycanopathy (congenital with intellectual disability), type B3;C3150417:Autosomal recessive limb-girdle muscular dystrophy type 2O;C3151519:Muscular dystrophy-dystroglycanopathy (congenital with brain and eye anomalies), type A3;C4310704:Retinitis pigmentosa 76 Pathogenic:1
- -
Muscular dystrophy-dystroglycanopathy (congenital with intellectual disability), type B3;C3150417:Autosomal recessive limb-girdle muscular dystrophy type 2O Pathogenic:1
This sequence change replaces isoleucine, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 337 of the POMGNT1 protein (p.Ile337Thr). This variant is present in population databases (rs138745073, gnomAD 0.01%). This missense change has been observed in individual(s) with clinical features of retinitis pigmentosa (internal data). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 285192). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) has been performed for this missense variant. However, the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on POMGNT1 protein function. In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. -
Inborn genetic diseases Uncertain:1
The c.1010T>C (p.I337T) alteration is located in exon 11 (coding exon 10) of the POMGNT1 gene. This alteration results from a T to C substitution at nucleotide position 1010, causing the isoleucine (I) at amino acid position 337 to be replaced by a threonine (T). The p.I337T alteration is predicted to be deleterious by in silico analysis. Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -
Muscular dystrophy-dystroglycanopathy Uncertain:1
The p.Ile337Thr variant in POMGNT1 has not been previously reported in the literature in individuals with muscular dystrophy-dystroglycanopathy, but has been identified in 0.01% (6/60000) of Admixed American chromosomes by the Genome Aggregation Database (gnomAD, http://gnomad.broadinstitute.org; dbSNP ID: rs138745073). Although this variant has been seen in the general population in a heterozygous state, its frequency is low enough to be consistent with a recessive carrier frequency. This variant has also been reported in ClinVar (VCV000285192.16) as likely pathogenic by Labcorp Genetics, and as a variant of uncertain significance by Eurofins Ntd Llc, Fulgent Genetics, GeneDx, Revvity Omics, Dept Of Ophthalmology (Nagoya University), and Ambry Genetics. Computational prediction tools and conservation analyses suggest that this variant may impact the protein, though this information is not predictive enough to determine pathogenicity. In summary, the clinical significance of the p.Ile337Thr variant is uncertain. ACMG/AMP Criteria applied: PM2_Supporting, PP3_moderate (Richards 2015). -
Retinal dystrophy Uncertain:1
- -
Muscle eye brain disease;C3150412:Muscular dystrophy-dystroglycanopathy (congenital with intellectual disability), type B3;C3150417:Autosomal recessive limb-girdle muscular dystrophy type 2O;C4310704:Retinitis pigmentosa 76 Uncertain:1
- -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at