chr22-28757145-C-A

Variant names:

• chr22-28757145-C-A
• rs757079729
• NM_172002.5:c.684C>A

Variant summary

Our verdict is Likely benign. The variant received -1 ACMG points: 2P and 3B. PM2 BP4_Moderate BP7

The NM_172002.5(HSCB):​c.684C>A​(p.Ile228Ile) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000296 in 1,554,526 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency:
  • Genomes: 𝑓 0.000046 (0 hom., cov: 32)
  • Exomes 𝑓: 0.000028 (0 hom.)
• Consequence: HSCB NM_172002.5 synonymous
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 0.426
• Publications: 0 publications found

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]

HSCB Gene-Disease associations (from GenCC):

• anemia, sideroblastic, 5

  Inheritance: Unknown Classification: LIMITED Submitted by: Labcorp Genetics (formerly Invitae)

ACMG classification

Our verdict: Likely_benign. The variant received -1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.24).
• BP7: Synonymous conserved (PhyloP=0.426 with no splicing effect.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_172002.5. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	HSCB	NM_172002.5	MANE Select	c.684C>A	p.Ile228Ile	synonymous	Exon 6 of 6	NP_741999.3
	HSCB	NM_001318316.2		c.216C>A	p.Ile72Ile	synonymous	Exon 6 of 6	NP_001305245.1
	HSCB	NM_001318314.2		c.*86C>A		3_prime_UTR	Exon 5 of 5	NP_001305243.1

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	HSCB	ENST00000216027.8	TSL:1 MANE Select	c.684C>A	p.Ile228Ile	synonymous	Exon 6 of 6	ENSP00000216027.3	Q8IWL3
	HSCB	ENST00000913001.1		c.678C>A	p.Ile226Ile	synonymous	Exon 6 of 6	ENSP00000583060.1
	HSCB	ENST00000910455.1		c.657C>A	p.Ile219Ile	synonymous	Exon 6 of 6	ENSP00000580514.1

Frequencies

GnomAD3 genomes AF: 0.0000460 AC: 7 AN: 152130 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.0000241

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

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: 0.0000882

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.0000160 AC: 4 AN: 250366 AF XY: 0.0000147

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: 0.0000353

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000278 AC: 39 AN: 1402396 Hom.: 0 Cov.: 24 AF XY: 0.0000314 AC XY: 22 AN XY: 700946

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.0000309 AC: 1 AN: 32342

American (AMR) AF: 0.00 AC: 0 AN: 44452

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 25666

East Asian (EAS) AF: 0.00 AC: 0 AN: 39350

South Asian (SAS) AF: 0.00 AC: 0 AN: 84902

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53202

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5284

European-Non Finnish (NFE) AF: 0.0000359 AC: 38 AN: 1058834

Other (OTH) AF: 0.00 AC: 0 AN: 58364

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.000000011486), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome AF: 0.0000460 AC: 7 AN: 152130 Hom.: 0 Cov.: 32 AF XY: 0.0000673 AC XY: 5 AN XY: 74308

African (AFR) AF: 0.0000241 AC: 1 AN: 41428

American (AMR) AF: 0.00 AC: 0 AN: 15250

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3470

East Asian (EAS) AF: 0.00 AC: 0 AN: 5200

South Asian (SAS) AF: 0.00 AC: 0 AN: 4828

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10608

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.0000882 AC: 6 AN: 68030

Other (OTH) AF: 0.00 AC: 0 AN: 2088

Alfa AF: 0.0000772 Hom.: 0

Bravo AF: 0.00000378

EpiCase AF: 0.0000545

EpiControl AF: 0.00

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.24
CADD	Benign	10
DANN	Benign	0.73
PhyloP100		0.43
Mutation Taster		=100/0	polymorphism

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

Other links and lift over

dbSNP: rs757079729; hg19: chr22-29153133;