17-59681366-G-A

Position:

• chr17-59681366-G-A

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM2 PP2

The NM_004859.4(CLTC):​c.3137G>A​(p.Arg1046His) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000205 in 1,461,674 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: CLTC NM_004859.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 10.0

Genes affected

CLTC (HGNC:2092): (clathrin heavy chain) Clathrin is a major protein component of the cytoplasmic face of intracellular organelles, called coated vesicles and coated pits. These specialized organelles are involved in the intracellular trafficking of receptors and endocytosis of a variety of macromolecules. The basic subunit of the clathrin coat is composed of three heavy chains and three light chains. [provided by RefSeq, Jul 2008]

PTRH2 (HGNC:24265): (peptidyl-tRNA hydrolase 2) The protein encoded by this gene is a mitochondrial protein with two putative domains, an N-terminal mitochondrial localization sequence, and a UPF0099 domain. In vitro assays suggest that this protein possesses peptidyl-tRNA hydrolase activity, to release the peptidyl moiety from tRNA, thereby preventing the accumulation of dissociated peptidyl-tRNA that could reduce the efficiency of translation. This protein also plays a role regulating cell survival and death. It promotes survival as part of an integrin-signaling pathway for cells attached to the extracellular matrix (ECM), but also promotes apoptosis in cells that have lost their attachment to the ECM, a process called anoikos. After loss of cell attachment to the ECM, this protein is phosphorylated, is released from the mitochondria into the cytosol, and promotes caspase-independent apoptosis through interactions with transcriptional regulators. This gene has been implicated in the development and progression of tumors, and mutations in this gene have been associated with an infantile multisystem neurologic, endocrine, and pancreatic disease (INMEPD) characterized by intellectual disability, postnatal microcephaly, progressive cerebellar atrophy, hearing impairment, polyneuropathy, failure to thrive, and organ fibrosis with exocrine pancreas insufficiency (PMID: 25574476). Alternative splicing results in multiple transcript variants encoding different isoforms. [provided by RefSeq, Mar 2015]

ACMG classification

Verdict is Uncertain_significance. Variant got 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in gene, where missense usually causes diseases (based on misZ statistic), CLTC. . Gene score misZ 7.7637 (greater than the threshold 3.09). Trascript score misZ 10.215 (greater than threshold 3.09). GenCC has associacion of gene with autosomal dominant non-syndromic intellectual disability, undetermined early-onset epileptic encephalopathy, intellectual disability, autosomal dominant 56.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
CLTC	NM_004859.4	c.3137G>A	p.Arg1046His	missense_variant	20/32	ENST00000269122.8	NP_004850.1
CLTC	NM_001288653.2	c.3149G>A	p.Arg1050His	missense_variant	20/32		NP_001275582.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
CLTC	ENST00000269122.8	c.3137G>A	p.Arg1046His	missense_variant	20/32	1	NM_004859.4	ENSP00000269122	P4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 250954 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135616

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 SAS exome AF: 0.0000327

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1461674 Hom.: 0 Cov.: 31 AF XY: 0.00000275 AC XY: 2 AN XY: 727134

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000116

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000180

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Intellectual disability, autosomal dominant 56 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Nov 15, 2021

The CLTC c.3149G>A (p.Arg1050His) variant is a missense variant. A literature search was performed for the gene, cDNA change, and amino acid change. No publications were found based on this search. This variant is located in a CHCR repeat of the heavy chain arm of the CLTC protein in which other de novo missense variants and small in-frame indels have been previously reported in individuals with CLTC-related neurodevelopmental disorder (Nabais Sa et al. 2020). The p.Arg1050His variant is reported at a frequency of 0.000033 in the South Asian population in version 2.1.1 of the Genome Aggregation Database, though this is based on one allele in a region of good sequence coverage so the variant is presumed to be rare. The variant is predicted to be deleterious by a majority of in silico predictors, but no functional studies have been conducted. Based on the available evidence, the p.Arg1050His variant is classified as a variant of uncertain significance for CLTC-related intellectual disability. -

Inborn genetic diseases Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Feb 26, 2020

The alteration results in an amino acid change:_x000D_ _x000D_ The c.3137G>A (p.R1046H) alteration is located in coding exon 20 of the CLTC gene. This alteration results from a G to A substitution at nucleotide position 3137, causing the arginine (R) at amino acid position 1046 to be replaced by a histidine (H). The alteration is rare in population databases: _x000D_ _x000D_ Based on data from the Genome Aggregation Database (gnomAD), the c.3137G>A alteration was observed in 0.0004% (1/250954) of total alleles studied. The altered amino acid is conserved throughout evolution:_x000D_ _x000D_ The p.R1046 amino acid is conserved in available vertebrate species. The amino acid is located in a functionally important protein domain:_x000D_ _x000D_ The p.R1046 amino acid is located in the clatherin heavy chain 4 (CHCR4) repeat motif, which is one of 7 repeats in the proximal leg region of the protein. This region helps form a structure for the trimerization of the protein (Brodsky, 2012). The alteration is predicted tolerated by in silico modeling:_x000D_ _x000D_ The p.R1046H alteration is predicted to be tolerated by in silico analysis. 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	Uncertain	0.55
BayesDel_addAF	Uncertain	0.071	D
BayesDel_noAF	Uncertain	-0.040
CADD	Pathogenic	28
DANN	Uncertain	1.0
DEOGEN2	Benign	0.29	T;.;T
Eigen	Uncertain	0.48
Eigen_PC	Uncertain	0.56
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.92	D;D;D
M_CAP	Benign	0.064	D
MetaRNN	Uncertain	0.66	D;D;D
MetaSVM	Benign	-0.73	T
MutationAssessor	Pathogenic	3.5	.;M;M
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Pathogenic	0.86	D
PROVEAN	Uncertain	-4.2	.;D;D
REVEL	Uncertain	0.43
Sift	Uncertain	0.022	.;D;D
Sift4G	Uncertain	0.037	D;D;D
Polyphen		0.19, 0.032	.;B;B
Vest4		0.73
MutPred		0.56		.;Gain of catalytic residue at I1044 (P = 0.0897);Gain of catalytic residue at I1044 (P = 0.0897);
MVP		0.78
MPC		1.8
ClinPred		0.97	D
GERP RS		5.3
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		0.39
gMVP		0.77

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.020		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: rs1376342815; hg19: chr17-57758727; COSMIC: COSV99292711; COSMIC: COSV99292711;