chr12-110127487-A-G

Position:

• chr12-110127487-A-G

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM2 PM5 PP3_Moderate

The NM_014055.4(IFT81):​c.107A>G​(p.Gln36Arg) 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 (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. Q36E) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 31)
• Consequence: IFT81 NM_014055.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 8.95

Genes affected

IFT81 (HGNC:14313): (intraflagellar transport 81) The protein encoded by this gene, together with IFT74, forms a tubulin-binding module of intraflagellar transport complex B. This module is involved in transport of tubulin within the cilium, and the encoded protein is required for ciliogenesis. Mutations in this gene are a cause of short-rib polydactyly syndromes. [provided by RefSeq, Dec 2016]

ACMG classification

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr12-110127486-C-G is described in Lovd as [Likely_pathogenic].
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.852

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
IFT81	NM_014055.4	c.107A>G	p.Gln36Arg	missense_variant	2/19	ENST00000242591.10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
IFT81	ENST00000242591.10	c.107A>G	p.Gln36Arg	missense_variant	2/19	1	NM_014055.4	P1

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD3 exomes AF: 0.00000411 AC: 1 AN: 243442 Hom.: 0 AF XY: 0.00000759 AC XY: 1 AN XY: 131672

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: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000901

Gnomad OTH exome AF: 0.00

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 31

ExAC AF: 0.00000824 AC: 1

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jun 22, 2023

This variant has not been reported in the literature in individuals affected with IFT81-related conditions. 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. Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt IFT81 protein function. ClinVar contains an entry for this variant (Variation ID: 2114214). The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the gnomAD database. This sequence change replaces glutamine, which is neutral and polar, with arginine, which is basic and polar, at codon 36 of the IFT81 protein (p.Gln36Arg). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.63
BayesDel_addAF	Pathogenic	0.44	D
BayesDel_noAF	Pathogenic	0.40
CADD	Pathogenic	26
DANN	Uncertain	1.0
DEOGEN2	Benign	0.41	.;T;T;.
Eigen	Pathogenic	0.95
Eigen_PC	Pathogenic	0.92
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.94	D;.;D;D
M_CAP	Uncertain	0.15	D
MetaRNN	Pathogenic	0.85	D;D;D;D
MetaSVM	Uncertain	0.59	D
MutationAssessor	Pathogenic	3.0	M;M;M;.
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Uncertain	0.59	T
PROVEAN	Uncertain	-3.5	D;D;D;D
REVEL	Pathogenic	0.86
Sift	Uncertain	0.0020	D;D;D;D
Sift4G	Pathogenic	0.0	D;D;D;D
Polyphen		0.99	D;D;D;.
Vest4		0.84
MutPred		0.50		Gain of phosphorylation at S39 (P = 0.0729);Gain of phosphorylation at S39 (P = 0.0729);Gain of phosphorylation at S39 (P = 0.0729);Gain of phosphorylation at S39 (P = 0.0729);
MVP		0.94
MPC		0.62
ClinPred		0.95	D
GERP RS		6.1
Varity_R		0.72
gMVP		0.86

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: rs780707962; hg19: chr12-110565292;