17-16025106-G-A

Variant names:

• chr17-16025106-G-A
• rs1042684635
• NM_017775.4:c.766G>A

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PM2 PP3_Strong

The NM_017775.4(TTC19):​c.766G>A​(p.Ala256Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000342 in 1,461,654 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 0.0000034 (0 hom.)
• Consequence: TTC19 NM_017775.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.79
• Publications: 1 publications found

Genes affected

TTC19 (HGNC:26006): (tetratricopeptide repeat domain 19) This gene encodes a protein with a tetratricopeptide repeat (TPR) domain containing several TPRs of about 34 aa each. These repeats are found in a variety of organisms including bacteria, fungi and plants, and are involved in a variety of functions including protein-protein interactions. This protein is embedded in the inner mitochondrial membrane and is involved in the formation of the mitochondrial respiratory chain III. It has also been suggested that this protein plays a role in cytokinesis. Mutations in this gene cause mitochondrial complex III deficiency. Alternatively spliced transcript variants have been found for this gene. [provided by RefSeq, Sep 2012]

TTC19 Gene-Disease associations (from GenCC):

• Leigh syndrome

  Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
• mitochondrial complex III deficiency nuclear type 2

  Inheritance: AR Classification: DEFINITIVE, STRONG, MODERATE Submitted by: Genomics England PanelApp, Ambry Genetics, G2P, Labcorp Genetics (formerly Invitae)
• mitochondrial complex III deficiency

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Likely_pathogenic. The variant received 6 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.959

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_017775.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TTC19	NM_017775.4	MANE Select	c.766G>A	p.Ala256Thr	missense	Exon 8 of 10	NP_060245.3
	TTC19	NM_001271420.2		c.445G>A	p.Ala149Thr	missense	Exon 8 of 10	NP_001258349.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TTC19	ENST00000261647.10	TSL:1 MANE Select	c.766G>A	p.Ala256Thr	missense	Exon 8 of 10	ENSP00000261647.5
	TTC19	ENST00000465567.1	TSL:1	n.489G>A		non_coding_transcript_exon	Exon 1 of 2
	TTC19	ENST00000470649.1	TSL:3	c.19G>A	p.Ala7Thr	missense	Exon 1 of 3	ENSP00000465627.1

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome AF: 0.00000342 AC: 5 AN: 1461654 Hom.: 0 Cov.: 31 AF XY: 0.00000275 AC XY: 2 AN XY: 727126

African (AFR) AF: 0.00 AC: 0 AN: 33468

American (AMR) AF: 0.00 AC: 0 AN: 44714

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26132

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86250

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53408

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5762

European-Non Finnish (NFE) AF: 0.00000450 AC: 5 AN: 1111842

Other (OTH) AF: 0.00 AC: 0 AN: 60378

GnomAD4 genome Cov.: 31

Alfa AF: 0.0000468 Hom.: 0

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Mitochondrial complex III deficiency nuclear type 2 Uncertain:1

Aug 11, 2017

Mayo Clinic Laboratories, Mayo Clinic

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.73
BayesDel_addAF	Pathogenic	0.46	D
BayesDel_noAF	Pathogenic	0.43
CADD	Pathogenic	29
DANN	Pathogenic	1.0
DEOGEN2	Uncertain	0.75	D
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.99
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Benign	0.84	T
M_CAP	Uncertain	0.27	D
MetaRNN	Pathogenic	0.96	D
MetaSVM	Pathogenic	0.98	D
MutationAssessor	Pathogenic	4.0	H
PhyloP100		7.8
PrimateAI	Uncertain	0.60	T
PROVEAN	Uncertain	-3.9	D
REVEL	Pathogenic	0.93
Sift	Pathogenic	0.0	D
Sift4G	Uncertain	0.014	D
Polyphen		1.0	D
Vest4		0.89
MutPred		0.83		Gain of phosphorylation at A256 (P = 0.0311)
MVP		0.94
MPC		0.61
ClinPred		1.0	D
GERP RS		5.9
PromoterAI		-0.011	Neutral
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.80
gMVP		0.63
Mutation Taster		=32/68	disease causing

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: rs1042684635; hg19: chr17-15928420;