10-104032120-T-C

Variant summary

Our verdict is Likely benign. Variant got -4 ACMG points: 0P and 4B. BP4_Strong

The NM_000494.4(COL17A1):c.*115A>G variant causes a 3 prime UTR change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00174 in 784,902 control chromosomes in the GnomAD database, including 3 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: 𝑓 0.0014 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0018 (3 hom.)
• Consequence: COL17A1 NM_000494.4 3_prime_UTR
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.521

Genes affected

COL17A1 (HGNC:2194): (collagen type XVII alpha 1 chain) This gene encodes the alpha chain of type XVII collagen. Unlike most collagens, collagen XVII is a transmembrane protein. Collagen XVII is a structural component of hemidesmosomes, multiprotein complexes at the dermal-epidermal basement membrane zone that mediate adhesion of keratinocytes to the underlying membrane. Mutations in this gene are associated with both generalized atrophic benign and junctional epidermolysis bullosa. Two homotrimeric forms of type XVII collagen exist. The full length form is the transmembrane protein. A soluble form, referred to as either ectodomain or LAD-1, is generated by proteolytic processing of the full length form. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Likely_benign. Variant got -4 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.79).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
COL17A1	NM_000494.4	c.*115A>G		3_prime_UTR_variant	56/56	ENST00000648076.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
COL17A1	ENST00000648076.2	c.*115A>G		3_prime_UTR_variant	56/56		NM_000494.4	A2
COL17A1	ENST00000369733.8	c.*115A>G		3_prime_UTR_variant	51/51	5		P4
COL17A1	ENST00000433822.1	c.*31+84A>G		intron_variant		5
COL17A1	ENST00000647647.1	c.*679A>G		3_prime_UTR_variant, NMD_transcript_variant	5/5

Frequencies

GnomAD3 genomes AF: 0.00141 AC: 215 AN: 152258 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.000386

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00144

Gnomad ASJ AF: 0.00663

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00145

Gnomad FIN AF: 0.000282

Gnomad MID AF: 0.00633

Gnomad NFE AF: 0.00204

Gnomad OTH AF: 0.00143

GnomAD4 exome AF: 0.00182 AC: 1149 AN: 632526 Hom.: 3 Cov.: 8 AF XY: 0.00184 AC XY: 624 AN XY: 339354

Gnomad4 AFR exome AF: 0.000520

Gnomad4 AMR exome AF: 0.00194

Gnomad4 ASJ exome AF: 0.00568

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00106

Gnomad4 FIN exome AF: 0.000502

Gnomad4 NFE exome AF: 0.00206

Gnomad4 OTH exome AF: 0.00210

GnomAD4 genome AF: 0.00140 AC: 214 AN: 152376 Hom.: 0 Cov.: 32 AF XY: 0.00133 AC XY: 99 AN XY: 74518

Gnomad4 AFR AF: 0.000385

Gnomad4 AMR AF: 0.00144

Gnomad4 ASJ AF: 0.00663

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00145

Gnomad4 FIN AF: 0.000282

Gnomad4 NFE AF: 0.00204

Gnomad4 OTH AF: 0.00142

Alfa AF: 0.00159 Hom.: 0

Bravo AF: 0.00154

Asia WGS AF: 0.000577 AC: 2 AN: 3478

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Junctional epidermolysis bullosa, non-Herlitz type Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 13, 2018

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.79
Cadd	Benign	6.6
Dann	Benign	0.79

Splicing

Name	Calibrated prediction	Score	Prediction
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

Publications

LitVar

Other links and lift over

dbSNP: rs543674750; hg19: chr10-105791878;