4-108832435-TA-T

Variant summary

Our verdict is Likely benign. Variant got -4 ACMG points: 2P and 6B. PM2 BP6_Moderate BS1

The NM_198721.4(COL25A1):c.1657-3del variant causes a splice region, splice polypyrimidine tract, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000958 in 1,586,440 control chromosomes in the GnomAD database, with no homozygous occurrence. 1/1 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Likely benign (★).

• Frequency:
  • Genomes: 𝑓 0.000013 (0 hom., cov: 32)
  • Exomes 𝑓: 0.00010 (0 hom.)
• Consequence: COL25A1 NM_198721.4 splice_region, splice_polypyrimidine_tract, intron
• Clinical Significance: Likely benign criteria provided, single submitter B:1
• Conservation: PhyloP100: 0.731

Genes affected

COL25A1 (HGNC:18603): (collagen type XXV alpha 1 chain) This gene encodes a brain-specific membrane associated collagen. A product of proteolytic processing of the encoded protein, CLAC (collagenous Alzheimer amyloid plaque component), binds to amyloid beta-peptides found in Alzheimer amyloid plaques but CLAC inhibits rather than facilitates amyloid fibril elongation (PMID: 16300410). A study of over-expression of this collagen in mice, however, found changes in pathology and behavior suggesting that the encoded protein may promote amyloid plaque formation (PMID: 19548013). Multiple transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Dec 2011]

ACMG classification

Verdict is Likely_benign. Variant got -4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP6: Variant 4-108832435-TA-T is Benign according to our data. Variant chr4-108832435-TA-T is described in ClinVar as [Likely_benign]. Clinvar id is 3035124.Status of the report is criteria_provided_single_submitter, 1 stars.
• BS1: Variant frequency is greater than expected in population amr. gnomad4_exome allele frequency = 0.000105 (150/1434698) while in subpopulation AMR AF= 0.000386 (16/41426). AF 95% confidence interval is 0.000242. There are 0 homozygotes in gnomad4_exome. There are 68 alleles in male gnomad4_exome subpopulation. Median coverage is 26. This position pass quality control queck.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
COL25A1	NM_198721.4	c.1657-3del		splice_region_variant, splice_polypyrimidine_tract_variant, intron_variant		ENST00000399132.6

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
COL25A1	ENST00000399132.6	c.1657-3del		splice_region_variant, splice_polypyrimidine_tract_variant, intron_variant		5	NM_198721.4

Frequencies

GnomAD3 genomes AF: 0.0000132 AC: 2 AN: 151742 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000294

Gnomad OTH AF: 0.00

GnomAD4 exome AF: 0.000105 AC: 150 AN: 1434698 Hom.: 0 Cov.: 26 AF XY: 0.0000952 AC XY: 68 AN XY: 714434

Gnomad4 AFR exome AF: 0.000155

Gnomad4 AMR exome AF: 0.000386

Gnomad4 ASJ exome AF: 0.000197

Gnomad4 EAS exome AF: 0.0000761

Gnomad4 SAS exome AF: 0.000108

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.000101

Gnomad4 OTH exome AF: 0.0000337

GnomAD4 genome AF: 0.0000132 AC: 2 AN: 151742 Hom.: 0 Cov.: 32 AF XY: 0.0000270 AC XY: 2 AN XY: 74098

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000294

Gnomad4 OTH AF: 0.00

Alfa AF: 0.000825 Hom.: 0

Bravo AF: 0.00000756

ClinVar

Significance: Likely benign

Submissions summary: Benign:1

Revision: criteria provided, single submitter

Submissions by phenotype

COL25A1-related disorder Benign:1

Likely benign, criteria provided, single submitter

clinical testing

PreventionGenetics, part of Exact Sciences

Aug 02, 2019

This variant is classified as likely benign based on ACMG/AMP sequence variant interpretation guidelines (Richards et al. 2015 PMID: 25741868, with internal and published modifications). -

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.040		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs760493024; hg19: chr4-109753591;