ClinVar Genomic variation as it relates to human health

The ATM c.6995T>C (p.Leu2332Pro) variant has a gnomAD v2.1.1 filtering allele frequency of 2.062% (African/African-American; exomes) which exceeds the ATM BA1 threshold of 0.50% (BA1). This variant has been observed in a homozygous and compound heterozygous state (presumed) in multiple individuals without biallelic disease (BP2_Strong; GTR Lab IDs: 61756, 500031). In silico protein predictors (ALIGN GVGD: Class C25; REVEL: 0.193; SIFT: tolerated; PolyPhen2: benign) predict that this alteration is not deleterious and in silico splicing predictors (SpliceAI: AL 0.01/DL 0.00/AG 0.00/DG 0.00; MaxEntScan: 0.00% (wild type = 9.04, variant = 9.04)) find that this variant is unlikely to affect splicing (BP4). In summary, this variant meets criteria to be classified as benign based on the ACMG/AMP criteria applied as specified by the HBOP Variant Curation Expert Panel.

Converted during submission to Likely benign.

This variant is considered likely benign or benign based on one or more of the following criteria: it is a conservative change, it occurs at a poorly conserved position in the protein, it is predicted to be benign by multiple in silico algorithms, and/or has population frequency not consistent with disease.

This alteration is classified as benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity.

This variant is considered benign. This variant has been observed at a population frequency that is significantly greater than expected given the associated disease prevalence and penetrance. This variant is strongly associated with less severe personal and family histories of cancer, typical for individuals without pathogenic variants in this gene [PMID: 25085752].

This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). No publications were found based on this search. Allele frequency data from public databases was too high to be consistent with this variant causing disease. Therefore, this variant is classified as benign.

ATM: BP4, BS1, BS2

The ATM p.Leu2332Pro variant was identified in 6 of 2720 proband chromosomes (frequency: 0.002) from American and Brazilian individuals or families with Lynch syndrome or sporadic breast cancer and was not identified in 200 chromosomes from healthy individuals (Yurgelun_2015_25980754 , Mangone_2015_25625042). The variant was also identified in dbSNP (ID: rs4988111) “With Likely benign, Uncertain significance allele”, ClinVar (classified benign by GeneDx, Ambry Genetics, Invitae; likely benign by Center for Pediatric Genomic Medicine (Children's Mercy Hospital and Clinics); and classification not provided by ITMI), Clinvitae (4x); and was not identified in GeneInsight-COGR, Cosmic, MutDB, and LOVD 3.0. The variant was identified in control databases in 557 (7 homozygous) of 276772 chromosomes at a frequency of 0.002 increasing the likelihood this could be a low frequency benign variant (Genome Aggregation Database Feb 27, 2017). Breakdown of the observations by population include African in 515 (7 homozygous) of 24026 chromosomes (freq: 0.02), Other in 4 of 6460 chromosomes (freq: 0.0006), Latino in 27 of 34410 chromosomes (freq: 0.0008), European Non-Finnish in 9 of 126350 chromosomes (freq: 0.00007), Ashkenazi Jewish in 1 of 10138 chromosomes (freq: 0.0001), and South Asian in 1 of 30780 chromosomes (freq: 0.00003) while not observed in the East Asian and European Finnish, populations. The p.Leu2332 residue is not conserved in mammals and four out of five computational analyses (PolyPhen-2, SIFT, AlignGVGD, BLOSUM, MutationTaster) do not suggest a high likelihood the variant Pro impacts the protein; however, this information is not predictive enough to rule out pathogenicity. The variant occurs outside of the splicing consensus sequence and in silico or computational prediction software programs (SpliceSiteFinder, MaxEntScan, NNSPLICE, GeneSplicer, HumanSpliceFinder) do not predict a difference in splicing. In summary, based on the above information this variant meets our laboratory's criteria to be classified as benign.