chr9-133351969-CAG-C
Variant summary
Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PVS1_ModeratePM2PP5_Very_Strong
The NM_003172.4(SURF1):c.845_846delCT(p.Ser282CysfsTer9) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000936 in 1,613,784 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Pathogenic (★★).
Frequency
Consequence
NM_003172.4 frameshift
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Pathogenic. Variant got 12 ACMG points.
Transcripts
RefSeq
Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | MANE | Protein | UniProt |
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SURF1 | NM_003172.4 | c.845_846delCT | p.Ser282CysfsTer9 | frameshift_variant | Exon 9 of 9 | ENST00000371974.8 | NP_003163.1 | |
SURF1 | NM_001280787.1 | c.518_519delCT | p.Ser173CysfsTer9 | frameshift_variant | Exon 8 of 8 | NP_001267716.1 |
Ensembl
Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | TSL | MANE | Protein | Appris | UniProt |
---|---|---|---|---|---|---|---|---|---|---|
SURF1 | ENST00000371974.8 | c.845_846delCT | p.Ser282CysfsTer9 | frameshift_variant | Exon 9 of 9 | 1 | NM_003172.4 | ENSP00000361042.3 | ||
SURF1 | ENST00000615505.4 | c.518_519delCT | p.Ser173CysfsTer9 | frameshift_variant | Exon 8 of 8 | 1 | ENSP00000482067.1 | |||
SURF1 | ENST00000437995.1 | n.755_756delCT | non_coding_transcript_exon_variant | Exon 8 of 8 | 5 | |||||
SURF1 | ENST00000495952.5 | n.835_836delCT | non_coding_transcript_exon_variant | Exon 5 of 5 | 2 |
Frequencies
GnomAD3 genomes AF: 0.0000854 AC: 13AN: 152210Hom.: 0 Cov.: 33
GnomAD3 exomes AF: 0.0000998 AC: 25AN: 250542Hom.: 0 AF XY: 0.000103 AC XY: 14AN XY: 135560
GnomAD4 exome AF: 0.0000944 AC: 138AN: 1461574Hom.: 0 AF XY: 0.0000935 AC XY: 68AN XY: 727050
GnomAD4 genome AF: 0.0000854 AC: 13AN: 152210Hom.: 0 Cov.: 33 AF XY: 0.0000941 AC XY: 7AN XY: 74358
ClinVar
Submissions by phenotype
Mitochondrial complex IV deficiency, nuclear type 1 Pathogenic:5
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The variant is observed at an extremely low frequency in the gnomAD v2.1.1 dataset (total allele frequency: 0.010%). Frameshift variant is predicted to result in a loss or disruption of normal protein function through protein truncation. Multiple pathogenic variants are reported in the predicted truncated region. It has been shared with similarly affected family member (3billion dataset). 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: 22488715). Therefore, this variant is classified as Pathogenic according to the recommendation of ACMG/AMP guideline. -
Evaluation: The homozygous deletion of the 2 bases AG at position 136218825 on Chr 9 was is covered with 155 reads and is found in 90% of the reads. Both parents are heterozygous carriers of the deletion at this position (cover 101 Reads in the father and 45% of the reads show the deletion, 112 reads in the mother and 40% show the deletion). This variant leads to a shift of the reading frame from position 282 followed by a stop codon after nine amino acids. To bioinformatic prediction, this variant leads to the loss of function of SURF1 and is therefore classified as pathogenic. This variant is classified according to ACMG guidelines are also classified as pathogenic. Classification according to ACMG guidelines of c.845_846delCT: - PVS1: The variant leads to a loss of function of the gene or gene product . - PM2: The variant was only tested with a very low frequency in population genetic studies. (like GnomAD, Iranome, GME, 1kGP, etc.) identified, and not in homozygous state observed. - PM3: The variant is homozygous in a recessively inherited disease. - PP3: Bioinformatic prediction programs such as GERP and MutationTaster grade this variant as pathogenic. - PP5: In ClinVar this variant is classified as pathogenic: https://www.ncbi.nlm.nih.gov/ Clinvar/RCV000331329/ The SURF1 gene encodes part of the assembly factor of the mitochondrial complex IV (COX), which is found in of the inner mitochondrial membrane and is involved in the biogenesis of cytochrome C oxidase complex is involved. Mutations in SURF1 (MIM#185620) are observed in patients with the recessively inherited nuclear mitochondrial complexes IV deficiency, type 1 (MIM#220110), which has been clinically described as Leigh Syndrome can manifest. In a review by Wedatilake et al (2013), a patient (27) with developmental delay hypotension, poor food intake, failure to thrive (poor weight gain) and developmental regression and respiratory insufficiency, which has the same variant (c.845_846delCT) in compound heterozygosity with a splice mutation. -
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Leigh syndrome Pathogenic:4
This variant was classified as: Pathogenic. -
This sequence change creates a premature translational stop signal (p.Ser282Cysfs*9) in the SURF1 gene. While this is not anticipated to result in nonsense mediated decay, it is expected to disrupt the last 19 amino acid(s) of the SURF1 protein. This variant is present in population databases (rs782316919, gnomAD 0.02%). This premature translational stop signal has been observed in individuals with autosomal recessive Leigh disease (PMID: 9837813, 16326995, 18583168, 22488715, 23829769). ClinVar contains an entry for this variant (Variation ID: 12770). For these reasons, this variant has been classified as Pathogenic. -
Variant summary: The SURF1 c.845_846delCT (p.Ser282Cysfs) variant results in a premature termination codon, predicted to cause a truncated or absent SURF1 protein due to nonsense mediated decay, which are commonly known mechanisms for disease. One in silico tool predicts a damaging outcome for this variant. This variant was found in 19/120666 control chromosomes at a frequency of 0.0001575, which does not exceed the estimated maximal expected allele frequency of a pathogenic SURF1 variant (0.0017678). The variant has been reported in numerous affected individuals in the literature, both in the homozygous and compound heterozygous state. In addition, multiple clinical diagnostic laboratories/reputable databases classified this variant as pathogenic. Taken together, this variant is classified as pathogenic. -
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not provided Pathogenic:4
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SURF1: PM3:Very Strong, PM2, PVS1:Moderate -
Frameshift variant predicted to result in protein truncation, as the last 19 amino acids are replaced with 8 different amino acids, and other loss-of-function variants have been reported downstream in the Human Gene Mutation Database (HGMD); Not observed at a significant frequency in large population cohorts (gnomAD); This variant is associated with the following publications: (PMID: 32020600, 23829769, 22488715, 29715184, 23408181, 16326995, 11317352, 26077850, 9837813, 18583168, 19780766, 31589614, 32709422, 34691145, 34490615) -
Inborn genetic diseases Pathogenic:1
The c.845_846delCT (p.S282Cfs*9) alteration, located in exon 9 (coding exon 9) of the SURF1 gene, consists of a deletion of 2 nucleotides from position 845 to 846, causing a translational frameshift with a predicted alternate stop codon after 9 amino acids. This alteration occurs at the 3' terminus of the SURF1 gene, is not expected to trigger nonsense-mediated mRNA decay, and only impacts the last 6% of the protein. However, premature stop codons are typically deleterious in nature (Ambry internal data). Based on data from gnomAD, the c.845_846delCT allele has an overall frequency of 0.010% (27/281946) total alleles studied. The highest observed frequency was 0.015% (19/128694) of European (non-Finnish) alleles. The c.845_856delCT deletion has been previously reported in multiple individuals with Leigh syndrome (Piekutowska-Abramczuk, 2009; Tiranti, 1998). Based on the available evidence, this alteration is classified as pathogenic. -
See cases Pathogenic:1
ACMG classification criteria: PVS1, PS4, PM3, PP1 -
Charcot-Marie-Tooth disease type 4K;C5435656:Mitochondrial complex IV deficiency, nuclear type 1 Pathogenic:1
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SURF1-related disorder Pathogenic:1
The SURF1 c.845_846delCT variant is predicted to result in a frameshift and premature protein termination (p.Ser282Cysfs*9). This variant, which is found at elevated frequencies in eastern European Slavic populations, has been reported in the compound heterozygous and homozygous states in many individuals with Leigh syndrome (Tiranti et al. 1998. PubMed ID: 9837813; Böhm et al. 2006. PubMed ID: 16326995; Lee et al. 2012. PubMed ID: 22488715; Lee et al. 2020. PubMed ID: 32020600; van der Ven et al. 2021. PubMed ID: 34490615; Kistol et al. 2023. PubMed ID: 36675121) and has been shown to co-segregate with disease in several affected families (Piekutowska-Abramczuk et al. 2009. PubMed ID: 19780766). Additionally, cultured fibroblasts and muscle cells from a homozygous individual were reported to only retain ~10% residual cytochrome oxidase activity (Tiranti et al. 1998. PubMed ID: 9837813). This variant is reported in 0.015% of alleles in individuals of European (Non-Finnish) descent in gnomAD. Frameshift variants in SURF1 are expected to be pathogenic. This variant is interpreted as pathogenic. -
Cerebellar ataxia;C0013362:Dysarthria;C0151786:Muscle weakness;C0234132:Abnormal pyramidal sign Pathogenic:1
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Leigh syndrome due to mitochondrial complex IV deficiency;C4225246:Charcot-Marie-Tooth disease type 4K Pathogenic:1
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Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at