16-75473444-G-A

Variant summary

Our verdict is Benign. Variant got -8 ACMG points: 2P and 10B. PM2 BP4_Strong BP6_Moderate BS1

The NM_021615.5(CHST6):c.*5197C>T variant causes a 3 prime UTR change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000204 in 152,302 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★).

• Frequency: Genomes: 𝑓 0.00020 (0 hom., cov: 32)
• Consequence: CHST6 NM_021615.5 3_prime_UTR
• Clinical Significance: Likely benign criteria provided, single submitter B:1
• Conservation: PhyloP100: -0.103

Genes affected

CHST6 (HGNC:6938): (carbohydrate sulfotransferase 6) The protein encoded by this gene is an enzyme that catalyzes the transfer of a sulfate group to the GlcNAc residues of keratan. Keratan sulfate helps maintain corneal transparency. Defects in this gene are a cause of macular corneal dystrophy (MCD). [provided by RefSeq, Jan 2010]

ACMG classification

Verdict is Benign. Variant got -8 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.95).
• BP6: Variant 16-75473444-G-A is Benign according to our data. Variant chr16-75473444-G-A is described in ClinVar as [Likely_benign]. Clinvar id is 887929.Status of the report is criteria_provided_single_submitter, 1 stars.
• BS1: Variant frequency is greater than expected in population afr. gnomad4 allele frequency = 0.000204 (31/152302) while in subpopulation AFR AF= 0.00065 (27/41570). AF 95% confidence interval is 0.000458. There are 0 homozygotes in gnomad4. There are 18 alleles in male gnomad4 subpopulation. Median coverage is 32. This position pass quality control queck.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CHST6	NM_021615.5	c.*5197C>T		3_prime_UTR_variant	3/3	ENST00000332272.9
CHST6	NR_163480.1	n.757C>T		non_coding_transcript_exon_variant	4/4
CHST6	NR_163481.1	n.601C>T		non_coding_transcript_exon_variant	3/3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CHST6	ENST00000332272.9	c.*5197C>T		3_prime_UTR_variant	3/3	3	NM_021615.5	P1
CHST6	ENST00000649341.1	c.*132C>T		3_prime_UTR_variant, NMD_transcript_variant	4/4
CHST6	ENST00000649824.1	c.*622C>T		3_prime_UTR_variant, NMD_transcript_variant	4/4

Frequencies

GnomAD3 genomes AF: 0.000204 AC: 31 AN: 152184 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.000651

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000196

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: 0.0000147

Gnomad OTH AF: 0.00

GnomAD4 exome Cov.: 0

GnomAD4 genome AF: 0.000204 AC: 31 AN: 152302 Hom.: 0 Cov.: 32 AF XY: 0.000242 AC XY: 18 AN XY: 74466

Gnomad4 AFR AF: 0.000650

Gnomad4 AMR AF: 0.000196

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000147

Gnomad4 OTH AF: 0.00

Alfa AF: 0.000142 Hom.: 0

Bravo AF: 0.000242

ClinVar

Significance: Likely benign

Submissions summary: Benign:1

Revision: criteria provided, single submitter

Submissions by phenotype

Macular corneal dystrophy Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 12, 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 and internal cut-off values, a variant classified as likely benign is not then subjected to further curation. The score for this variant resulted in a classification of likely benign for this disease. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.95
Cadd	Benign	1.8
Dann	Benign	0.53

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: rs554016597; hg19: chr16-75507342;