chr1-228158992-C-T
Variant summary
Our verdict is Likely benign. Variant got -6 ACMG points: 0P and 6B. BP4_ModerateBS2
The NM_020435.4(GJC2):c.1234C>T(p.His412Tyr) variant causes a missense change. The variant allele was found at a frequency of 0.000956 in 1,603,620 control chromosomes in the GnomAD database, including 3 homozygotes. In-silico tool predicts a benign outcome for this variant. 12/20 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).
Frequency
Consequence
NM_020435.4 missense
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Likely_benign. Variant got -6 ACMG points.
Transcripts
RefSeq
Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | MANE | Protein | UniProt |
---|---|---|---|---|---|---|---|---|
GJC2 | NM_020435.4 | c.1234C>T | p.His412Tyr | missense_variant | Exon 2 of 2 | ENST00000366714.3 | NP_065168.2 |
Ensembl
Frequencies
GnomAD3 genomes AF: 0.000927 AC: 141AN: 152162Hom.: 0 Cov.: 33
GnomAD3 exomes AF: 0.000748 AC: 169AN: 225966Hom.: 0 AF XY: 0.000719 AC XY: 90AN XY: 125230
GnomAD4 exome AF: 0.000959 AC: 1392AN: 1451458Hom.: 3 Cov.: 33 AF XY: 0.000938 AC XY: 677AN XY: 721648
GnomAD4 genome AF: 0.000927 AC: 141AN: 152162Hom.: 0 Cov.: 33 AF XY: 0.000700 AC XY: 52AN XY: 74324
ClinVar
Submissions by phenotype
not provided Uncertain:4Benign:2
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Identified in individual with segmental dystonia, spasticity, and hypomyelination who also harbored 2 additional GJC2 variants (Zittel et al., 2012); Published functional studies demonstrate impaired transfer of Lucifer yellow dye in cells transfected with H412Y (described as H409Y), supporting altered gap junction function (Finegold et al., 2012); 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: 22351697, 29906362, 22833003) -
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The GJC2 c.1234C>T; p.His412Tyr variant (rs200334298), also known as H409Y, is reported in the literature in individuals affected with vascular and lymphatic malformations (Finegold 2012, Michelini 2016, Serio 2022). Additionally, this variant has been reported in an individual with Pelizaeus-Merzbacher-like disease, a form of hypomyelinating leukodystrophy (Zittel 2012). This variant is found in the non-Finnish European population with an allele frequency of 0.1402% (161/114,842 alleles) in the Genome Aggregation Database. Functional analyses of the variant protein show impaired function (Finegold 2012). Computational analyses are uncertain whether this variant is neutral or deleterious (REVEL: 0.5). While this variant is unlikely to be causative of autosomal dominant lymphatic malformations, due to limited and conflicting information, its clinical significance in recessive disease is uncertain at this time. References: Finegold DN et al. Connexin 47 mutations increase risk for secondary lymphedema following breast cancer treatment. Clin Cancer Res. 2012 Apr 15;18(8):2382-90. PMID: 22351697. Michelini S et al. Genetic Screening in a Large Cohort of Italian Patients Affected by Primary Lymphedema Using a Next Generation Sequencing (NGS) Approach. Lymphology. 2016 Jun;49(2):57-72. PMID: 29906362. Serio VB et al. Nosological and Theranostic Approach to Vascular Malformation through cfDNA NGS Liquid Biopsy. J Clin Med. 2022 Jun 28;11(13):3740. PMID: 35807022. Zittel S et al. "Pelizaeus-Merzbacher-like disease" presenting as complicated hereditary spastic paraplegia. J Neurol. 2012 Nov;259(11):2498-500. PMID: 22833003. -
not specified Uncertain:1
Variant summary: GJC2 c.1234C>T (p.His412Tyr) results in a conservative amino acid change in the encoded protein sequence. Four of five in-silico tools predict a benign effect of the variant on protein function. The variant allele was found at a frequency of 0.00075 in 225966 control chromosomes (genomAD). c.1234C>T has been reported in the literature in individuals affected with lymphedema or PelizaeusMerzbacher-like disease (Finegold_2012, Zittel_2012, Michelini_2016). These reports do not provide unequivocal conclusions about association of the variant with Hypomyelinating Leukodystrophy 2. At least one functional study reports experimental evidence evaluating an impact on protein function, however, does not allow convincing conclusions about the variant effect (Finegold_2012). Seven ClinVar submitters (evaluation after 2014) cite this variant as uncertain significance. The following publications have been ascertained in the context of this evaluation (PMID: 22351697, 29906362, 35807022, 22833003). Based on the evidence outlined above, the variant was classified as uncertain significance. -
Spastic paraplegia Uncertain:1
This sequence change replaces histidine, which is basic and polar, with tyrosine, which is neutral and polar, at codon 412 of the GJC2 protein (p.His412Tyr). This variant is present in population databases (rs200334298, gnomAD 0.1%), and has an allele count higher than expected for a pathogenic variant. This missense change has been observed in individual(s) with lymphedema and/or Pelizaeus-Merzbacher-like disease (PMID: 22351697, 22833003, 29906362). This variant is also known as H409Y. ClinVar contains an entry for this variant (Variation ID: 445910). 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 GJC2 protein function. Experimental studies have shown that this missense change affects GJC2 function (PMID: 22351697). In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -
Inborn genetic diseases Uncertain:1
The c.1234C>T (p.H412Y) alteration is located in exon 2 (coding exon 1) of the GJC2 gene. This alteration results from a C to T substitution at nucleotide position 1234, causing the histidine (H) at amino acid position 412 to be replaced by a tyrosine (Y). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -
Hereditary spastic paraplegia Uncertain:1
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Hypomyelinating leukodystrophy 2 Uncertain:1
This missense variant (c.1234C>T, p.His214Tyr) has been observed at very low frequency in population databases. It has been reported in the literature (PMID:22351697, PMID 22833003). Variant prediction programs provide no consensus as to the pathogenicity of the variant, and no functional studies have been published. -
Hypomyelinating leukodystrophy 2;C2750784:Hereditary spastic paraplegia 44;C4747646:Lymphatic malformation 3 Uncertain:1
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Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at