X-154420244-T-TA

Position:

• chrX-154420244-T-TA

Variant summary

Our verdict is Pathogenic. Variant got 10 ACMG points: 10P and 0B. PVS1 PM2

The NM_000116.5(TAFAZZIN):​c.680dup​(p.Tyr227Ter) variant causes a stop gained, frameshift change. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Uncertain significance (★). Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 23)
• Consequence: TAFAZZIN NM_000116.5 stop_gained, frameshift
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 6.56

Genes affected

TAFAZZIN (HGNC:11577): (tafazzin, phospholipid-lysophospholipid transacylase) This gene encodes a protein that is expressed at high levels in cardiac and skeletal muscle. Mutations in this gene have been associated with a number of clinical disorders including Barth syndrome, dilated cardiomyopathy (DCM), hypertrophic DCM, endocardial fibroelastosis, and left ventricular noncompaction (LVNC). Multiple transcript variants encoding different isoforms have been described. A long form and a short form of each of these isoforms is produced; the short form lacks a hydrophobic leader sequence and may exist as a cytoplasmic protein rather than being membrane-bound. Other alternatively spliced transcripts have been described but the full-length nature of all these transcripts is not known. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Pathogenic. Variant got 10 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TAFAZZIN	NM_000116.5	c.680dup	p.Tyr227Ter	stop_gained, frameshift_variant	9/11	ENST00000601016.6	NP_000107.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TAFAZZIN	ENST00000601016.6	c.680dup	p.Tyr227Ter	stop_gained, frameshift_variant	9/11	1	NM_000116.5	ENSP00000469981

Frequencies

GnomAD3 genomes Cov.: 23

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 23

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Left ventricular noncompaction Uncertain:1

Uncertain significance, criteria provided, single submitter

research

Institute Of Molecular Biology And Genetics, Federal Almazov National Medical Research Centre

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The boy presented with muscle hypotonia and dilated cardiomyopathy in combination with left ventricular non-compaction and heart failure at 2 month old. Transient hyponeutrophilia was also observed. Similar genetic variant in TAZ gene was detected in patient's mother who is asymptomatic. Based on the clinical phenotype the probability of the variant to be causative is very high. However, according ton ACMG this variant currently is classified as VUS. -

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.13		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: rs1557194203; hg19: chrX-153648583;