17-50199747-C-T

Variant names:

• chr17-50199747-C-T
• rs753705753
• NM_000088.4:c.298+6G>A

Variant summary

Our verdict is Likely benign. The variant received -2 ACMG points: 2P and 4B. PM2 BP4_Strong

The NM_000088.4(COL1A1):​c.298+6G>A variant causes a splice region, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000206 in 1,458,850 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: COL1A1 NM_000088.4 splice_region, intron
• Scores: Splicing: ADA: 0.00007653
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.279
• Publications: 0 publications found

Genes affected

COL1A1 (HGNC:2197): (collagen type I alpha 1 chain) This gene encodes the pro-alpha1 chains of type I collagen whose triple helix comprises two alpha1 chains and one alpha2 chain. Type I is a fibril-forming collagen found in most connective tissues and is abundant in bone, cornea, dermis and tendon. Mutations in this gene are associated with osteogenesis imperfecta types I-IV, Ehlers-Danlos syndrome type VIIA, Ehlers-Danlos syndrome Classical type, Caffey Disease and idiopathic osteoporosis. Reciprocal translocations between chromosomes 17 and 22, where this gene and the gene for platelet-derived growth factor beta are located, are associated with a particular type of skin tumor called dermatofibrosarcoma protuberans, resulting from unregulated expression of the growth factor. Two transcripts, resulting from the use of alternate polyadenylation signals, have been identified for this gene. [provided by R. Dalgleish, Feb 2008]

TILAM (HGNC:52795): (long intergenic non-protein coding RNA 1969)

ACMG classification

Our verdict: Likely_benign. The variant received -2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.8).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
COL1A1	NM_000088.4	c.298+6G>A		splice_region_variant, intron_variant	Intron 2 of 50	ENST00000225964.10	NP_000079.2
COL1A1	XM_011524341.2	c.298+6G>A		splice_region_variant, intron_variant	Intron 2 of 47		XP_011522643.1
COL1A1	XM_005257058.5	c.298+6G>A		splice_region_variant, intron_variant	Intron 2 of 48		XP_005257115.2
COL1A1	XM_005257059.5	c.298+6G>A		splice_region_variant, intron_variant	Intron 2 of 37		XP_005257116.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
COL1A1	ENST00000225964.10	c.298+6G>A		splice_region_variant, intron_variant	Intron 2 of 50	1	NM_000088.4	ENSP00000225964.6
COL1A1	ENST00000507689.1	c.352+6G>A		splice_region_variant, intron_variant	Intron 1 of 3	2		ENSP00000460459.1
COL1A1	ENST00000474644.1	n.417+6G>A		splice_region_variant, intron_variant	Intron 2 of 3	3
TILAM	ENST00000509943.2	n.-129C>T		upstream_gene_variant		3

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD2 exomes AF: 0.00000412 AC: 1 AN: 242556 AF XY: 0.00000755

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000924

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000206 AC: 3 AN: 1458850 Hom.: 0 Cov.: 35 AF XY: 0.00000276 AC XY: 2 AN XY: 725710

African (AFR) AF: 0.00 AC: 0 AN: 33426

American (AMR) AF: 0.00 AC: 0 AN: 44688

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26082

East Asian (EAS) AF: 0.00 AC: 0 AN: 39686

South Asian (SAS) AF: 0.00 AC: 0 AN: 86168

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 52584

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 4600

European-Non Finnish (NFE) AF: 0.00000270 AC: 3 AN: 1111404

Other (OTH) AF: 0.00 AC: 0 AN: 60212

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Osteogenesis imperfecta type I Uncertain:1

Feb 16, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change falls in intron 2 of the COL1A1 gene. It does not directly change the encoded amino acid sequence of the COL1A1 protein. It affects a nucleotide within the consensus splice site. This variant is present in population databases (no rsID available, gnomAD 0.0009%). This variant has not been reported in the literature in individuals affected with COL1A1-related conditions. Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant is not likely to affect RNA splicing. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.80
CADD	Benign	7.8
DANN	Benign	0.72
PhyloP100		0.28
PromoterAI		-0.066	Neutral

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.000077
dbscSNV1_RF	Benign	0.020
SpliceAI score (max)		0.0		Details are displayed if max score is > 0.2

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

Other links and lift over

dbSNP: rs753705753; hg19: chr17-48277108;