chr2-38074853-GC-G
Variant summary
Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1PM2PP5_Very_Strong
The NM_000104.4(CYP1B1):c.535delG(p.Ala179ArgfsTer18) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000512 in 1,563,088 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Pathogenic (★★).
Frequency
Consequence
NM_000104.4 frameshift
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Pathogenic. Variant got 18 ACMG points.
Transcripts
RefSeq
Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | MANE | Protein | UniProt |
---|---|---|---|---|---|---|---|---|
CYP1B1 | NM_000104.4 | c.535delG | p.Ala179ArgfsTer18 | frameshift_variant | Exon 2 of 3 | ENST00000610745.5 | NP_000095.2 |
Ensembl
Frequencies
GnomAD3 genomes AF: 0.0000591 AC: 9AN: 152238Hom.: 0 Cov.: 33
GnomAD3 exomes AF: 0.0000512 AC: 8AN: 156224Hom.: 0 AF XY: 0.0000467 AC XY: 4AN XY: 85666
GnomAD4 exome AF: 0.0000503 AC: 71AN: 1410732Hom.: 0 Cov.: 31 AF XY: 0.0000531 AC XY: 37AN XY: 697332
GnomAD4 genome AF: 0.0000591 AC: 9AN: 152356Hom.: 0 Cov.: 33 AF XY: 0.0000671 AC XY: 5AN XY: 74508
ClinVar
Submissions by phenotype
Glaucoma 3A Pathogenic:4
The variant is observed at an extremely low frequency in the gnomAD v2.1.1 dataset (total allele frequency: 0.001%). Predicted Consequence/Location: The variant is located in a mutational hot spot and/or well-established functional domain in which established pathogenic variants have been reported. Missense changes are a common disease-causing mechanism. Functional studies provide strong evidence of the variant having a damaging effect on the gene or gene product (PMID: 22711529). In silico tool predictions suggest damaging effect of the variant on gene or gene product [REVEL: 0.95 (>=0.6, sensitivity 0.68 and specificity 0.92); 3Cnet: 0.96 (>=0.6, sensitivity 0.72 and precision 0.9)]. Same nucleotide change resulting in same amino acid change has been previously reported as pathogenic/likely pathogenic with strong evidence (ClinVar ID: VCV000013333 /PMID: 11704759 /3billion dataset). The variant has been previously reported as de novo in at least two similarly affected unrelated individuals (3billion dataset). The variant has been reported to co-segregate with the disease in at least 7 similarly affected relatives/individuals in at least two unrelated families (PMID: 11704759, 12325025, 12634870, 16498234). Therefore, this variant is classified as Pathogenic according to the recommendation of ACMG/AMP guideline. -
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ACMG classification criteria: PVS1 very strong, PM2 supporting, PM3 strong -
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Anterior segment dysgenesis 6 Pathogenic:2
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not provided Pathogenic:2
The c.535delG variant in the CYP1B1 gene has been reported previously in association with autosomal recessive primary congenital glaucoma, and has been reported as a founder mutation in the Moroccan population (Belmouden et al., 2002; Gronskov et al., 2016). This variant causes a frameshift starting with codon Alanine 179, changes this amino acid to an Arginine residue, and creates a premature Stop codon at position 18 of the new reading frame, denoted p.Ala179ArgfsX18. This variant is predicted to cause loss of normal protein function either through protein truncation or nonsense-mediated mRNA decay. The c.535delG variant is observed in 4/26120 (0.015%) alleles from individuals of Latino background and 7/182840 (0.004%) global alleles in large population cohorts, with no homozygotes identified (Lek et al., 2016). We interpret c.535delG as a pathogenic variant. -
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Glaucoma 3, primary infantile, B;C1856439:Glaucoma 3A;C4310623:Anterior segment dysgenesis 6 Pathogenic:1
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Primary congenital glaucoma Pathogenic:1
Variant summary: CYP1B1 c.535delG (p.Ala179ArgfsX18) results in a premature termination codon, predicted to cause a truncation of the encoded protein or absence of the protein due to nonsense mediated decay, which are commonly known mechanisms for disease. The variant allele was found at a frequency of 5.1e-05 in 156224 control chromosomes (gnomAD). c.535delG has been reported in the literature in at least an individual affected with Primary Congenital Glaucoma (example: Reis_2016). These data indicate that the variant may be associated with disease. The following publication has been ascertained in the context of this evaluation (PMID: 27272408). ClinVar contains an entry for this variant (Variation ID: 523943). Based on the evidence outlined above, the variant was classified as pathogenic. -
CYP1B1-related disorder Pathogenic:1
The CYP1B1 c.535delG variant is predicted to result in a frameshift and premature protein termination (p.Ala179Argfs*18). This variant was reported in the homozygous or compound heterozygous state to be causative for primary congenital glaucoma (described as 4339delG, Bouyacoub et al. 2014. PubMed ID: 24942078; Cardoso et al. 2015. PubMed ID: 25952714; García-Antón et al. 2017. PubMed ID: 28448622). This variant is reported in 0.019% of alleles in individuals of Latino descent in gnomAD (http://gnomad.broadinstitute.org/variant/2-38301996-GC-G). Frameshift variants in CYP1B1 are expected to be pathogenic. This variant is interpreted as pathogenic. -
Congenital glaucoma Pathogenic:1
This sequence change creates a premature translational stop signal (p.Ala179Argfs*18) in the CYP1B1 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in CYP1B1 are known to be pathogenic (PMID: 9097971, 9497261, 19234632). This variant is present in population databases (rs771076928, gnomAD 0.02%). This premature translational stop signal has been observed in individuals with open-angle glaucoma, and primary congenital glaucoma (PMID: 12372064, 19234632, 23922489, 27272408, 27777502, 27820421). It has also been observed to segregate with disease in related individuals. This variant is also known as c.4339delG, c.906delG, c.534_535delG (p.Ala179ArgfsX16). ClinVar contains an entry for this variant (Variation ID: 523943). For these reasons, this variant has been classified as Pathogenic. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at