rs145303331
Variant summary
Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PM1PM2PP5_Very_Strong
The NM_004278.4(PIGL):c.500T>C(p.Leu167Pro) variant causes a missense change. The variant allele was found at a frequency of 0.000739 in 1,605,302 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Pathogenic (★★).
Frequency
Consequence
NM_004278.4 missense
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Pathogenic. Variant got 12 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes AF: 0.000604 AC: 92AN: 152236Hom.: 0 Cov.: 32
GnomAD3 exomes AF: 0.000414 AC: 104AN: 251422Hom.: 0 AF XY: 0.000383 AC XY: 52AN XY: 135884
GnomAD4 exome AF: 0.000754 AC: 1095AN: 1452948Hom.: 0 Cov.: 30 AF XY: 0.000728 AC XY: 525AN XY: 721112
GnomAD4 genome AF: 0.000597 AC: 91AN: 152354Hom.: 0 Cov.: 32 AF XY: 0.000550 AC XY: 41AN XY: 74508
ClinVar
Submissions by phenotype
CHIME syndrome Pathogenic:10Uncertain:1
This variant was classified as: Uncertain significance. -
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The PIGL c.500T>C (p.Leu167Pro) variant has been reported in a compound heterozygous state with either a frameshift variant, a nonsense variant or a large deletion in six patients with clinical features of coloboma, congenital heart disease, ichthyosiform dermatosis, intellectual disability, and ear anomalies (CHIME) syndrome from five unrelated families (Ng et al. 2012). All evaluated parents and siblings of the patients were found to be heterozygous carriers of the variant. Control data are unavailable for the p.Leu167Pro variant, which is reported at a frequency of 0.00091 in the European (Finnish) population of the Exome Aggregation Consortium. The variant is present in a highly conserved residue in the catalytic domain of the protein. Cell lines derived from a patient who was compound heterozygous for the p.Leu167Pro variant and a chromosome 17 deletion were deficient in two glycosylphosphatidylinositol markers, demonstrating a detrimental functional effect of the variant. Based on the evidence from the literature, the p.Leu167Pro variant is classified as pathogenic for coloboma, congenital heart disease, ichthyosiform dermatosis, intellectual disability, and ear anomalies syndrome. This variant was observed by ICSL as part of a predisposition screen in an ostensibly healthy population. -
Variant summary: PIGL c.500T>C (p.Leu167Pro) results in a non-conservative amino acid change in the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 0.00041 in 251422 control chromosomes (gnomAD). c.500T>C has been reported in the literature in multiple compound heterozygous and homozygous individuals affected with CHIME Syndrome (Ng_2012, Murakami_2014). These data indicate that the variant is very likely to be associated with disease. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. 12 ClinVar submitters (evaluation after 2014) cite the variant as uncertain significance (n=1) and pathogenic (n=11). Based on the evidence outlined above, the variant was classified as pathogenic. -
Same nucleotide change resulting in same amino acid change has been previously reported as pathogenic/likely pathogenic with strong evidence (ClinVar ID: VCV000030544, PMID:22444671). The variant has been reported to be in trans with a pathogenic variant as either compound heterozygous or homozygous in at least 2 similarly affected unrelated individuals(PMID: 22444671, PM3_S) In silico tool predictions suggest damaging effect of the variant on gene or gene product (REVEL: 0.791>=0.6, 3CNET: 0.856>=0.75).It is observed at an extremely low frequency in the gnomAD v2.1.1 dataset (total allele frequency: 0.0005153). 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 CHIME syndrome (MIM#280000). (I) 0106 - This gene is associated with autosomal recessive disease. (I) 0200 - Variant is predicted to result in a missense amino acid change from leucine to proline. (I) 0251 - This variant is heterozygous. (I) 0304 - Variant is present in gnomAD <0.01 for a recessive condition (v2: 130 heterozygotes, 0 homozygotes). (SP) 0502 - Missense variant with conflicting in silico predictions and high conservation. (I) 0600 - Variant is located in the annotated PIG-L domain (DECIPHER). (I) 0705 - No comparable missense variants have previous evidence for pathogenicity. (I) 0801 - This variant has strong previous evidence of pathogenicity in unrelated individuals. It has been reported as pathogenic in multiple unrelated individuals with CHIME syndrome (PMID: 22444671). Additionally, it has been reported as pathogenic by multiple clinical testing laboratories (ClinVar). (SP) 1010 - Functional evidence for this variant is inconclusive. A fibroblast cell line from an individual with compound heterozygous variants NM_004278.3:c.427-1G>A and NM_004278.3:c.500T>C showed deficiency in cell surface GPI anchor markers, CD59 and aerolysin (PMID: 22444671). (I) 1201 - Heterozygous variant detected in trans with a second pathogenic heterozygous variant (NM_004278.3:c.427-1G>A) in a recessive disease. (I) 1206 - This variant has been shown to be paternally inherited (by trio analysis). (I) Legend: (SP) - Supporting pathogenic, (I) - Information, (SB) - Supporting benign -
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not provided Pathogenic:9
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In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 29473937, 31980526, 22444671, 24784135, 23561846, 28371479, 25250048, 8893234, 7666399, 3041916, 31535386, 31127708) -
This sequence change replaces leucine, which is neutral and non-polar, with proline, which is neutral and non-polar, at codon 167 of the PIGL protein (p.Leu167Pro). This variant is present in population databases (rs145303331, gnomAD 0.07%), and has an allele count higher than expected for a pathogenic variant. This missense change has been observed in individual(s) with CHIME syndrome (PMID: 22444671, 28371479). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. ClinVar contains an entry for this variant (Variation ID: 30544). 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 PIGL protein function with a positive predictive value of 80%. For these reasons, this variant has been classified as Pathogenic. -
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Inborn genetic diseases Pathogenic:1
The c.500T>C (p.L167P) alteration is located in exon 5 (coding exon 5) of the PIGL gene. This alteration results from a T to C substitution at nucleotide position 500, causing the leucine (L) at amino acid position 167 to be replaced by a proline (P). Based on data from the Genome Aggregation Database (gnomAD), the PIGL c.500T>C alteration was observed in 0.05% (130/282820) of total alleles studied, with a frequency of 0.07% (94/129144) in the European (non-Finnish) subpopulation. This mutation has been reported in the compound heterozygous state in several individuals with CHIME syndrome as well as one homozygous individual (Ng, 2012; Knight Johnson, 2017; Ceroni, 2018). It was also identified in the homozygous state in siblings with non-syndromic ichthyosis (Onoufriadis, 2020). This amino acid position is highly conserved in available vertebrate species. The p.L167P alteration is predicted to be deleterious by in silico analysis. Based on the available evidence, this alteration is classified as pathogenic. -
Coloboma, Congenital Heart Disease, Ichthyosiform Dermatosis, Intellectual Disability, and Ear Anomalies (CHIME) Syndrome Pathogenic:1
The c.500T>C (p.Leu167Pro) variant has been reported in a compound heterozygous state with either a frameshift variant, a nonsense variant or a large deletion in six patients with coloboma, congenital heart disease, ichthyosiform dermatosis, intellectual disability, and ear anomalies syndrome from five unrelated families (Ng et al. 2012). All evaluated parents and siblings of the parents were found to be heterozygous carriers of the variant. Control data are unavailable for the p.Leu167Pro variant, which is reported at a frequency of 0.00091 in the European (Finnish) population of the Exome Aggregation Consortium. The variant is present in a highly conserved residue in the catalytic domain of the protein. Cell lines derived from a patient who was compound heterozygous for the p.Leu167Pro variant and a chromosome 17 deletion were deficient in two glycosylphosphatidylinositol markers, demonstrating a detrimental functional effect of the variant. Based on the evidence from the literature, the p.Leu167Pro variant is classified as pathogenic for coloboma, congenital heart disease, ichthyosiform dermatosis, intellectual disability, and ear anomalies syndrome. -
Hypertelorism;C0151526:Premature birth;C0239234:Low-set ears;C0409348:Camptodactyly of finger;C0431659:Hypoplasia of scrotum;C0431904:Postaxial hand polydactyly;C1398522:Bilateral cleft lip and palate;C1827524:Wide intermamillary distance Uncertain:1
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PIGL-related disorder Other:1
Variant classified as Likely pathogenic and reported on 06-14-2019 by Lab or GTR ID 26957. GenomeConnect assertions are reported exactly as they appear on the patient-provided report from the testing laboratory. GenomeConnect staff make no attempt to reinterpret the clinical significance of the variant. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at