chrX-154532990-C-T
Variant summary
Our verdict is Likely pathogenic. Variant got 7 ACMG points: 8P and 1B. PP5_Very_StrongBP4
The NM_001360016.2(G6PD):c.1003G>A(p.Ala335Thr) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00013 in 1,210,823 control chromosomes in the GnomAD database, with no homozygous occurrence. There are 81 hemizygotes in GnomAD. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★★).
Frequency
Consequence
NM_001360016.2 missense
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Likely_pathogenic. Variant got 7 ACMG points.
Transcripts
RefSeq
Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | MANE | Protein | UniProt |
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G6PD | NM_001360016.2 | c.1003G>A | p.Ala335Thr | missense_variant | Exon 9 of 13 | ENST00000393562.10 | NP_001346945.1 | |
G6PD | NM_000402.4 | c.1093G>A | p.Ala365Thr | missense_variant | Exon 9 of 13 | NP_000393.4 | ||
G6PD | NM_001042351.3 | c.1003G>A | p.Ala335Thr | missense_variant | Exon 9 of 13 | NP_001035810.1 |
Ensembl
Frequencies
GnomAD3 genomes AF: 0.0000798 AC: 9AN: 112723Hom.: 0 Cov.: 24 AF XY: 0.0000860 AC XY: 3AN XY: 34873
GnomAD3 exomes AF: 0.000192 AC: 35AN: 182482Hom.: 0 AF XY: 0.000341 AC XY: 23AN XY: 67366
GnomAD4 exome AF: 0.000135 AC: 148AN: 1098045Hom.: 0 Cov.: 33 AF XY: 0.000215 AC XY: 78AN XY: 363445
GnomAD4 genome AF: 0.0000798 AC: 9AN: 112778Hom.: 0 Cov.: 24 AF XY: 0.0000859 AC XY: 3AN XY: 34938
ClinVar
Submissions by phenotype
Anemia, nonspherocytic hemolytic, due to G6PD deficiency Pathogenic:13Uncertain:1
Variant found in unrelated hemizygotes with deficiency, some with anemia, jaundice, favism, and CNSHA (PS4_M, PP4). In one family, three brothers all have variant and CNSHA (PP1). Decreased activity in red blood cells (0-32%) (PS3). Predicted to be disease causing by Mutation Taster, probably damaging by PolyPhen, and damaging by SIFT (PP3). Below expected carrier frequency in gnomAD (PM2). Reported as pathogenic by multiple clinical testing groups (PP5). Post_P 0.999 (odds of pathogenicity 6563, Prior_P 0.1). -
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The missense c.1003G>A(p.Ala335Thr) variant in G6PD gene has been reported previously in homozygous or hemizygous states in multiple individuals affected with G6PD deficiency (Gandomani MG, et. al., 2011; Al-Allawi N, et. al., 2010; Kawamoto F, et. al., 2006). Experimental studies indicate that this variant causes decreased affinity for glucose-6-phosphate and a significant reduction of thermostability, affecting G6PD function (Gandomani MG, et. al., 2011). The p.Ala335Thr variant has been reported with allele frequency of 0.02% in gnomAD Exomes and is novel (not in any individuals) in 1000 Genomes. This variant has been reported to the ClinVar database as Uncertain Significance / Pathogenic (multiple submissions). The amino acid change p.Ala335Thr in G6PD is predicted as conserved by GERP++ and PhyloP across 100 vertebrates. The amino acid Ala at position 335 is changed to a Thr changing protein sequence and it might alter its composition and physico-chemical properties. For these reasons, this variant has been classified as Pathogenic. -
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This sequence change replaces alanine, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 335 of the G6PD protein (p.Ala335Thr). This variant is present in population databases (rs5030869, gnomAD 0.1%), and has an allele count higher than expected for a pathogenic variant. This missense change has been observed in individuals with glucose-6-phosphatedehydrogenase deficiency (PMID: 3393536, 11499668, 12497642, 15315792, 16927025, 20602793, 21677401, 22293322, 25548459, 26060661). This variant is also known as the Chatham variant. ClinVar contains an entry for this variant (Variation ID: 10363). 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) indicates that this missense variant is expected to disrupt G6PD protein function with a positive predictive value of 95%. Experimental studies have shown that this missense change affects G6PD function (PMID: 3393536). This variant disrupts the p.Ala335 amino acid residue in G6PD. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 7803800, 15625830, 25775246). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. For these reasons, this variant has been classified as Pathogenic. -
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The variant is observed at an allele frequency greater than expected for the associated disorder in the gnomAD v2.1.1 dataset. However, this variant is the second most common variant of G6PD deficiency in several Middle-East countries and in some provinces of Iran (ClinVar ID: VCV000010363). Predicted Consequence/Location: Missense changes are a common disease-causing mechanism. In silico tool predictions suggest damaging effect of the variant on gene or gene product (REVEL: 0.61; 3Cnet: 0.95). Same nucleotide change resulting in same amino acid change has been previously reported as pathogenic/likely pathogenic with strong evidence (ClinVar ID: VCV000010363 /PMID: 3393536). Different missense changes at the same codon (p.Ala335Asp, p.Ala335Val) have been reported as pathogenic/likely pathogenic with strong evidence (ClinVar ID: VCV001068217 /PMID: 25775246, 7803800). Therefore, this variant is classified as Pathogenic according to the recommendation of ACMG/AMP guideline. -
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Based on the classification scheme VCGS_Germline_v1.3.4, this variant is classified as Pathogenic. Following criteria are met: 0102 - Loss of function is a known mechanism of disease in this gene and is associated with G6PD deficient haemolytic anaemia (favism) (MIM#300908). (I) 0109 - This gene is associated with X-linked recessive disease. Hemizygous males and homozygous females are commonly affected; however, some heterozygous female carriers can also be affected depending on X-inactivation. (I) 0200 - Variant is predicted to result in a missense amino acid change from alanine to threonine. (I) 0253 - This variant is hemizygous. (I) 0304 - Variant is present in gnomAD (v2) <0.01 for a recessive condition (12 heterozygotes, 0 homozygotes, 23 hemizygotes). (SP) 0309 - Multiple alternative amino acid changes at the same position have been observed in gnomAD (v2) (highest allele count: 1 heterozygote, 0 homozygotes, 0 hemizygotes). (I) 0502 - Missense variant with conflicting in silico predictions and uninformative conservation. (I) 0600 - Variant is located in the annotated glucose-6-phosphate dehydrogenase, C-terminal domain (DECIPHER). (I) 0801 - This variant has strong previous evidence of pathogenicity in unrelated individuals. This variant has been reported many times as pathogenic, and described as the Chatham variant (ClinVar, PMID: 33100726). (SP) 1205 - This variant has been shown to be maternally inherited (by trio analysis). (I) -
This variant in exon 9 of the G6PD gene results in the amino acid substitution from Alanine to Threonine at codon 365 (p.Ala365Thr) with the sequence change of c.1093G>A (NM_000402.4). This variant was observed in a proband with decreased level of G6PD enzyme (3.8 U/dL) which was screened for advanced newborn screening with confirmatory genetic reflex testing at lifecell diagnostics. The reference base is conserved in mammals and in-silico predictions by Polyphen and SIFT are damaging. The Missense Variants Z-Score for this variant is 2.60. Missense Variants Z-Score is produced by the Exome Aggregation Consortium (60,706 adult humans) by computing a signed Z score for the deviation of observed counts from the expected number. Positive Z scores indicate increased constraint (intolerance to variation) and therefore that the gene had fewer missense variants than expected. The G6PD c.1093G>A; p.Ala365Thr variant, also referred to as c.1003G>A; p.Ala335Thr, commonly known as Chatham variant, causes class II of G6PD deficiency characterized by possessing less than 10% of normal enzyme activity, which makes it one of the most severe forms of G6PD deficiency (Gandomani et al. 2011; PMID:21677401). This variant has been reported in multiple individuals affected with glucose-6-phosphatedehydrogenase deficiency and is the second most common variant in several Middle-East countries and in some provinces of Iran (Kashmoola et al., 2015; PMID:25548459, Rahimi Z et al., 2006; PMID:16938474, Iwai et al., PMID:11499668). Experimental studies have shown that this missense change affects substrate affinity and stability of the glucose-6-phosphate dehydrogenase protein (Vulliamy et al., 1988; PMID:3393536) -
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not provided Pathogenic:6
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In silico analysis indicates that this missense variant does not alter protein structure/function; This variant is associated with the following publications: (PMID: 21931771, 27391121, 28376293, 28824188, 21173806, 14505231, 16927025, 3393536, 28069791, 27980749, 28132692, 34272389, 33069889, 34426522, 12215013, 36007526, 28902532, 38225994, 36150187, 37260775, 38085718, 38480019, 37415281, 37119244, 12028056, 36681081, 36746659) -
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G6PD: PM2, PM5, PS3:Moderate, PS4:Moderate, PP1, PP4 -
The G6PD c.1003G>A; p.Ala335Thr variant (rs5030869), commonly known as G6PD Chatham, is one of the most common G6PD deficiency alleles worldwide and is considered a Class II variant with severe enzymatic deficiency (Gandomani 2011, Mesbah-Namin 2002, Vulliamy 1988). This variant is reported in ClinVar (Variation ID: 10363) and is found predominantly in the South Asian population with an overall allele frequency of 0.13% (25/19065 alleles, including 19 hemizygotes) in the Genome Aggregation Database (v2.1.1). Computational analyses are uncertain whether this variant is neutral or deleterious (REVEL: 0.609). Based on available information, this variant is considered to be pathogenic. References: Gandomani MG et al. Molecular identification of G6PD Chatham (G1003A) in Khuzestan province of Iran. J Genet. 2011 Apr;90(1):143-5. PMID: 21677401. Mesbah-Namin SA et al. Three major glucose-6-phosphate dehydrogenase-deficient polymorphic variants identified in Mazandaran state of Iran. Br J Haematol. 2002 Jun;117(3):763-4. PMID: 12028056. Vulliamy TJ et al. Diverse point mutations in the human glucose-6-phosphate dehydrogenase gene cause enzyme deficiency and mild or severe hemolytic anemia. Proc Natl Acad Sci U S A. 1988 Jul;85(14):5171-5. PMID: 3393536. -
Inborn genetic diseases Pathogenic:1
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Malaria, susceptibility to;C2720289:Anemia, nonspherocytic hemolytic, due to G6PD deficiency Pathogenic:1
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Malaria, susceptibility to Pathogenic:1
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G6PD-related disorder Pathogenic:1
The G6PD c.1003G>A variant is predicted to result in the amino acid substitution p.Ala335Thr. This variant, also known as G6PD Chatham, has previously been reported to be causative for glucose 6 phosphate dehydrogenase deficiency (Vulliamy et al. 1988. PubMed ID: 3393536; Al-Allawi et al. 2010. PubMed ID: 20602793; Iwai et al. 2001. PubMed ID: 11499668). This variant is reported in 0.13% of alleles in individuals of South Asian descent in gnomAD and has been interpreted as pathogenic in ClinVar (https://www.ncbi.nlm.nih.gov/clinvar/variation/10363/). This variant is interpreted as pathogenic. -
G6PD CHATHAM Other:1
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Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at