6-41930703-G-C

Position:

• chr6-41930703-G-C

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM2 PP3_Strong

The NM_004053.4(BYSL):​c.639G>C​(p.Trp213Cys) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 12/21 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: BYSL NM_004053.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 9.66

Genes affected

BYSL (HGNC:1157): (bystin like) Bystin is expressed as a 2-kb major transcript and a 3.6-kb minor transcript in SNG-M cells and in human trophoblastic teratocarcinoma HT-H cells. Protein binding assays determined that bystin binds directly to trophinin and tastin, and that binding is enhanced when cytokeratins 8 and 18 are present. Immunocytochemistry of HT-H cells showed that bystin colocalizes with trophinin, tastin, and the cytokeratins, suggesting that these molecules form a complex in trophectoderm cells at the time of implantation. Using immunohistochemistry it was determined that trophinin and bystin are found in the placenta from the sixth week of pregnancy. Both proteins were localized in the cytoplasm of the syncytiotrophoblast in the chorionic villi and in endometrial decidual cells at the uteroplacental interface. After week 10, the levels of trophinin, tastin, and bystin decreased and then disappeared from placental villi. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.983

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
BYSL	NM_004053.4	c.639G>C	p.Trp213Cys	missense_variant	4/7	ENST00000230340.9	NP_004044.3
BYSL	XM_047419281.1	c.393G>C	p.Trp131Cys	missense_variant	4/7		XP_047275237.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
BYSL	ENST00000230340.9	c.639G>C	p.Trp213Cys	missense_variant	4/7	1	NM_004053.4	ENSP00000230340	P1
BYSL	ENST00000489290.1	c.500G>C	p.Gly167Ala	missense_variant, NMD_transcript_variant	3/6	3		ENSP00000417813
BYSL	ENST00000372996.2	c.312G>C	p.Trp104Cys	missense_variant, NMD_transcript_variant	3/6	5		ENSP00000362087

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Mar 25, 2024

The c.639G>C (p.W213C) alteration is located in exon 4 (coding exon 4) of the BYSL gene. This alteration results from a G to C substitution at nucleotide position 639, causing the tryptophan (W) at amino acid position 213 to be replaced by a cysteine (C). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.33	D
BayesDel_noAF	Pathogenic	0.24
CADD	Pathogenic	32
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.66	D
Eigen	Pathogenic	1.0
Eigen_PC	Pathogenic	0.93
FATHMM_MKL	Pathogenic	0.97	D
LIST_S2	Pathogenic	0.98	D
M_CAP	Pathogenic	0.30	D
MetaRNN	Pathogenic	0.98	D
MetaSVM	Uncertain	0.65	D
MutationAssessor	Pathogenic	3.4	M
MutationTaster	Benign	1.0	D
PrimateAI	Pathogenic	0.84	D
PROVEAN	Pathogenic	-12	D
REVEL	Pathogenic	0.78
Sift	Uncertain	0.0010	D
Sift4G	Pathogenic	0.0010	D
Polyphen		1.0	D
Vest4		0.96
MutPred		0.90		Loss of MoRF binding (P = 0.0582);
MVP		0.94
MPC		1.4
ClinPred		1.0	D
GERP RS		5.2
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.94
gMVP		0.89

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

No publications associated with this variant yet.

Other links and lift over

hg19: chr6-41898441;