rs775883520

chr8-93780603-A-G

Variant summary

Our verdict is Pathogenic. Variant got 14 ACMG points: 14P and 0B. PM1 PM2 PP3_Moderate PP5_Very_Strong

The NM_153704.6(TMEM67):c.725A>G(p.Asn242Ser) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000929 in 1,614,094 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 Likely pathogenic (★★).

• Frequency:
  • Genomes: 𝑓 0.000013 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000089 (0 hom.)
• Consequence: TMEM67 NM_153704.6 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:9
• Conservation: PhyloP100: 8.62

Genes affected

TMEM67 (HGNC:28396): (transmembrane protein 67) The protein encoded by this gene localizes to the primary cilium and to the plasma membrane. The gene functions in centriole migration to the apical membrane and formation of the primary cilium. Multiple transcript variants encoding different isoforms have been found for this gene. Defects in this gene are a cause of Meckel syndrome type 3 (MKS3) and Joubert syndrome type 6 (JBTS6). [provided by RefSeq, Nov 2008]

ACMG classification

Verdict is Pathogenic. Variant got 14 ACMG points.

• PM1: In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 4 uncertain in NM_153704.6
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.857
• PP5: Variant 8-93780603-A-G is Pathogenic according to our data. Variant chr8-93780603-A-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 216826.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr8-93780603-A-G is described in Lovd as [Likely_pathogenic]. Variant chr8-93780603-A-G is described in Lovd as [Likely_pathogenic]. Variant chr8-93780603-A-G is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TMEM67	NM_153704.6	c.725A>G	p.Asn242Ser	missense_variant	8/28	ENST00000453321.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TMEM67	ENST00000453321.8	c.725A>G	p.Asn242Ser	missense_variant	8/28	1	NM_153704.6	P1

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152164 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.0000241

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.00000796 AC: 2 AN: 251250 Hom.: 0 AF XY: 0.00000736 AC XY: 1 AN XY: 135778

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000289

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.0000544

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000889 AC: 13 AN: 1461812 Hom.: 0 Cov.: 32 AF XY: 0.00000413 AC XY: 3 AN XY: 727198

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000447

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000348

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000629

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome AF: 0.0000131 AC: 2 AN: 152282 Hom.: 0 Cov.: 32 AF XY: 0.0000134 AC XY: 1 AN XY: 74470

Gnomad4 AFR AF: 0.0000241

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.000207

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00

Bravo AF: 0.00000756

ExAC AF: 0.0000165 AC: 2

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:9

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:3

Pathogenic, criteria provided, single submitter	clinical testing	CeGaT Center for Human Genetics Tuebingen	Oct 01, 2017	- -
Pathogenic, criteria provided, single submitter	clinical testing	Genomic Research Center, Shahid Beheshti University of Medical Sciences	May 03, 2020	- -
Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Jan 10, 2023	In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Not observed at significant frequency in large population cohorts (gnomAD); This variant is associated with the following publications: (PMID: 26260382, 29302074, 25920555, 26092869, 30315573, 32000717, 33726816, 35032046, 28719906, 27491411) -

Joubert syndrome 6 Pathogenic:2

Pathogenic, criteria provided, single submitter	research	UW Hindbrain Malformation Research Program, University of Washington	Feb 23, 2015	- -
Pathogenic, criteria provided, single submitter	research	Broad Center for Mendelian Genomics, Broad Institute of MIT and Harvard	Dec 03, 2018	The homozygous p.Asn242Ser variant in TMEM67 was identified by our study in one individual with Joubert syndrome. The p.Asn242Ser variant in TMEM67 was reported in 23 individuals (including 22 Iranians) with Joubert syndrome, segregated with disease in 22 affected relatives from 9 families (PMID: 28719906, 19574260), and has been identified in 0.002978% (1/33580) of Latino chromosomes by the Genome Aggregation Database (gnomAD, http://gnomad.broadinstitute.org; dbSNP rs775883520). Although this variant has been seen in the general population, its frequency is low enough to be consistent with a recessive carrier frequency and its prevalence in Iranian families with a shared haplotype suggests this is a founder variant (PMID: 28719906). Computational prediction tools and conservation analyses suggest that this variant may impact the protein, though this information is not predictive enough to determine pathogenicity. This variant was also reported likely pathogenic in ClinVar prior to the publication of a paper about 22 Iranians from 9 families with this variant and Joubert syndrome (Variation ID: 216826). Two additional variants at the the same position, p.Asn242Thr and p.Asn242Lys, have been reported in association with disease in the literature, supporting that a change at this position may not be tolerated (PMID: 23559409, 19574260). Position 242 in the TMEM67 protein has also been reported as a glycosylation site for GlcNAc, providing additional support that a change in this position may not be tolerated (Entry: Q5HYA8) In summary, this variant meets criteria to be classified as pathogenic for Joubert syndrome in an autosomal recessive manner based on the predicted impact of a change at position 242 in TMEM67 and cosegregation with Joubertssyndrome in multiple Iranian families. ACMG/AMP Criteria applied: PM2, PP3, PM5, PM1_Supporting, PP1_Strong (Richards 2015). -

Meckel-Gruber syndrome;C0431399:Familial aplasia of the vermis Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Invitae

Jul 19, 2023

ClinVar contains an entry for this variant (Variation ID: 216826). This missense change has been observed in individual(s) with Joubert syndrome (PMID: 26092869, 27491411, 28719906). It has also been observed to segregate with disease in related individuals. This variant is present in population databases (rs775883520, gnomAD 0.003%). This sequence change replaces asparagine, which is neutral and polar, with serine, which is neutral and polar, at codon 242 of the TMEM67 protein (p.Asn242Ser). 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 TMEM67 protein function. For these reasons, this variant has been classified as Pathogenic. -

Inborn genetic diseases Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Nov 28, 2016

- -

COACH syndrome 1 Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

3billion

Sep 01, 2022

The variant is observed at an extremely low frequency in the gnomAD v2.1.1 dataset (total allele frequency: <0.001%). Missense changes are a common disease-causing mechanism. In silico tool predictions suggest damaging effect of the variant on gene or gene product (REVEL: 0.84; 3Cnet: 0.91). Same nucleotide change resulting in same amino acid change has been previously reported as pathogenic/likely pathogenic with strong evidence (ClinVar ID: VCV000216826). Different missense changes at the same codon (p.Asn242Lys, p.Asn242Thr) have been reported to be associated with TMEM67 -related disorder (PMID: 19574260 , 23559409). Therefore, this variant is classified as Likely pathogenic according to the recommendation of ACMG/AMP guideline. -

Abnormality of the nervous system Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Kariminejad - Najmabadi Pathology & Genetics Center

Jul 10, 2021

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.17
BayesDel_addAF	Uncertain	0.16	D
BayesDel_noAF	Uncertain	0.070
Cadd	Uncertain	25
Dann	Uncertain	1.0
DEOGEN2	Uncertain	0.67	D;D;.
Eigen	Pathogenic	0.78
Eigen_PC	Pathogenic	0.78
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Uncertain	0.94	D;D;D
M_CAP	Pathogenic	0.33	D
MetaRNN	Pathogenic	0.86	D;D;D
MetaSVM	Pathogenic	1.1	D
MutationTaster	Benign	1.0	D;D
PrimateAI	Uncertain	0.53	T
PROVEAN	Uncertain	-4.0	D;D;D
REVEL	Pathogenic	0.84
Sift	Pathogenic	0.0	D;D;D
Sift4G	Pathogenic	0.0	D;D;D
Polyphen		0.99	.;D;.
Vest4		0.91, 0.90
MutPred		0.61		.;Loss of stability (P = 0.0382);.;
MVP		1.0
MPC		0.40
ClinPred		0.99	D
GERP RS		5.8
Varity_R		0.33
gMVP		0.90

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: rs775883520; hg19: chr8-94792831;