2-27444470-A-C

Position:

• chr2-27444470-A-C

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM2 PP3_Moderate

The NM_015662.3(IFT172):​c.5212T>G​(p.Cys1738Gly) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: IFT172 NM_015662.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 8.75

Genes affected

IFT172 (HGNC:30391): (intraflagellar transport 172) This gene encodes a subunit of the intraflagellar transport subcomplex IFT-B. Subcomplexes IFT-A and IFT-B are necessary for ciliary assembly and maintenance. Mutations in this gene have been associated with skeletal ciliopathies, with or without polydactyly, such as such short-rib thoracic dysplasias 1, 9 or 10. [provided by RefSeq, Mar 2014]

KRTCAP3 (HGNC:28943): (keratinocyte associated protein 3) Predicted to be integral component of membrane. [provided by Alliance of Genome Resources, Apr 2022]

ACMG classification

Verdict is Uncertain_significance. Variant got 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.909

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
IFT172	NM_015662.3	c.5212T>G	p.Cys1738Gly	missense_variant	48/48	ENST00000260570.8	NP_056477.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
IFT172	ENST00000260570.8	c.5212T>G	p.Cys1738Gly	missense_variant	48/48	1	NM_015662.3	ENSP00000260570	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Short-rib thoracic dysplasia 10 with or without polydactyly;C4225342:Retinitis pigmentosa 71 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jul 17, 2023

This sequence change replaces cysteine, which is neutral and slightly polar, with glycine, which is neutral and non-polar, at codon 1738 of the IFT172 protein (p.Cys1738Gly). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with IFT172-related conditions. ClinVar contains an entry for this variant (Variation ID: 842989). An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be disruptive. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.27
BayesDel_addAF	Pathogenic	0.27	D
BayesDel_noAF	Pathogenic	0.14
CADD	Pathogenic	28
DANN	Uncertain	0.98
DEOGEN2	Uncertain	0.72	D
Eigen	Pathogenic	0.81
Eigen_PC	Pathogenic	0.79
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Benign	0.84	T
M_CAP	Uncertain	0.14	D
MetaRNN	Pathogenic	0.91	D
MetaSVM	Benign	-0.46	T
MutationAssessor	Uncertain	2.7	M
MutationTaster	Benign	1.0	D;D
PrimateAI	Uncertain	0.61	T
PROVEAN	Pathogenic	-7.8	D
REVEL	Uncertain	0.59
Sift	Benign	0.053	T
Sift4G	Uncertain	0.046	D
Polyphen		0.99	D
Vest4		0.85
MutPred		0.71		Gain of disorder (P = 0.0071);
MVP		0.61
MPC		0.57
ClinPred		0.99	D
GERP RS		5.6
Varity_R		0.76
gMVP		0.83

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: rs1664849569; hg19: chr2-27667337;