chr22-28742163-G-A

Position:

• chr22-28742163-G-A

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_172002.5(HSCB):​c.68G>A​(p.Arg23Lys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000274 in 1,461,468 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 14/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000027 (0 hom.)
• Consequence: HSCB NM_172002.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 1.02

Genes affected

HSCB (HGNC:28913): (HscB mitochondrial iron-sulfur cluster cochaperone) This gene encodes a DnaJ-type co-chaperone and member of the heat shock cognate B (HscB) family of proteins. The encoded protein plays a role in the synthesis of iron-sulfur clusters, protein cofactors that are involved in the redox reactions of mitochondrial electron transport and other processes. Cells in which this gene is knocked down exhibit reduced activity of iron-sulfur cluster-dependent enzymes including succinate dehydrogenase and aconitase. The encoded protein may stimulate the ATPase activity of the mitochondrial stress-70 protein. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Dec 2015]

CHEK2 (HGNC:16627): (checkpoint kinase 2) In response to DNA damage and replication blocks, cell cycle progression is halted through the control of critical cell cycle regulators. The protein encoded by this gene is a cell cycle checkpoint regulator and putative tumor suppressor. It contains a forkhead-associated protein interaction domain essential for activation in response to DNA damage and is rapidly phosphorylated in response to replication blocks and DNA damage. When activated, the encoded protein is known to inhibit CDC25C phosphatase, preventing entry into mitosis, and has been shown to stabilize the tumor suppressor protein p53, leading to cell cycle arrest in G1. In addition, this protein interacts with and phosphorylates BRCA1, allowing BRCA1 to restore survival after DNA damage. Mutations in this gene have been linked with Li-Fraumeni syndrome, a highly penetrant familial cancer phenotype usually associated with inherited mutations in TP53. Also, mutations in this gene are thought to confer a predisposition to sarcomas, breast cancer, and brain tumors. This nuclear protein is a member of the CDS1 subfamily of serine/threonine protein kinases. Several transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Apr 2012]

ACMG classification

Verdict is Uncertain_significance. Variant got 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.17383832).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
HSCB	NM_172002.5	c.68G>A	p.Arg23Lys	missense_variant	1/6	ENST00000216027.8	NP_741999.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
HSCB	ENST00000216027.8	c.68G>A	p.Arg23Lys	missense_variant	1/6	1	NM_172002.5	ENSP00000216027	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000403 AC: 1 AN: 247944 Hom.: 0 AF XY: 0.00000742 AC XY: 1 AN XY: 134684

Gnomad AFR exome AF: 0.0000638

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000274 AC: 4 AN: 1461468 Hom.: 0 Cov.: 32 AF XY: 0.00000275 AC XY: 2 AN XY: 727030

Gnomad4 AFR exome AF: 0.0000299

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 8.99e-7

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome Cov.: 32

Alfa AF: 0.0000370 Hom.: 0

Bravo AF: 0.00000378

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

Sep 16, 2021

The c.68G>A (p.R23K) alteration is located in exon 1 (coding exon 1) of the HSCB gene. This alteration results from a G to A substitution at nucleotide position 68, causing the arginine (R) at amino acid position 23 to be replaced by a lysine (K). 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	Benign	0.11
BayesDel_addAF	Benign	-0.21	T
BayesDel_noAF	Benign	-0.54
CADD	Benign	21
DANN	Benign	0.96
DEOGEN2	Benign	0.033	T;.
Eigen	Benign	-0.53
Eigen_PC	Benign	-0.48
FATHMM_MKL	Benign	0.54	D
LIST_S2	Benign	0.56	T;.
M_CAP	Benign	0.0036	T
MetaRNN	Benign	0.17	T;T
MetaSVM	Benign	-1.0	T
MutationAssessor	Benign	1.4	L;.
MutationTaster	Benign	0.77	N;N;N
PrimateAI	Uncertain	0.49	T
PROVEAN	Benign	-0.32	N;N
REVEL	Benign	0.032
Sift	Benign	0.057	T;T
Sift4G	Benign	0.25	T;T
Polyphen		0.056	B;.
Vest4		0.34
MVP		0.50
MPC		0.18
ClinPred		0.083	T
GERP RS		2.8
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.6
Varity_R		0.071
gMVP		0.34

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: rs1569180952; hg19: chr22-29138151;