16-75540046-A-G

Position:

• chr16-75540046-A-G

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_001077418.3(TMEM231):​c.899T>C​(p.Ile300Thr) variant causes a missense change. The variant allele was found at a frequency of 0.00000137 in 1,461,410 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/21 in silico tools predict a benign 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. I300V) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: TMEM231 NM_001077418.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 4.00

Genes affected

TMEM231 (HGNC:37234): (transmembrane protein 231) This gene encodes a transmembrane protein, which is a component of the B9 complex involved in the formation of the diffusion barrier between the cilia and plasma membrane. Mutations in this gene cause Joubert syndrome (JBTS). Multiple alternatively spliced transcript variants have been found for this gene. [provided by RefSeq, Jan 2013]

ACMG classification

Verdict is Uncertain_significance. Variant got 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.25699776).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TMEM231	NM_001077418.3	c.899T>C	p.Ile300Thr	missense_variant	7/7	ENST00000258173.11
TMEM231	NM_001077416.2	c.1058T>C	p.Ile353Thr	missense_variant	6/6
TMEM231	NR_074083.2	n.1065T>C		non_coding_transcript_exon_variant	7/7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TMEM231	ENST00000258173.11	c.899T>C	p.Ile300Thr	missense_variant	7/7	1	NM_001077418.3	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461410 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 726980

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000252

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Joubert syndrome 20;C3809352:Meckel syndrome, type 11 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Sep 01, 2022

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. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Tolerated"; PolyPhen-2: "Not Available"; Align-GVGD: "Class C0"). ClinVar contains an entry for this variant (Variation ID: 1488753). This variant has not been reported in the literature in individuals affected with TMEM231-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces isoleucine, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 353 of the TMEM231 protein (p.Ile353Thr). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.22
BayesDel_addAF	Benign	-0.070	T
BayesDel_noAF	Benign	-0.34
CADD	Benign	16
DANN	Benign	0.83
DEOGEN2	Benign	0.11	T;.;T
Eigen	Benign	-0.31
Eigen_PC	Benign	-0.33
FATHMM_MKL	Uncertain	0.91	D
LIST_S2	Benign	0.71	T;T;T
M_CAP	Benign	0.025	T
MetaRNN	Benign	0.26	T;T;T
MetaSVM	Benign	-0.90	T
MutationAssessor	Benign	1.1	L;.;.
MutationTaster	Benign	1.0	N;N;N
PrimateAI	Benign	0.36	T
PROVEAN	Benign	-2.2	N;.;N
REVEL	Benign	0.15
Sift	Benign	0.091	T;.;T
Sift4G	Benign	0.073	T;T;T
Polyphen		0.025	B;.;.
Vest4		0.070
MutPred		0.68		Loss of sheet (P = 0.0126);.;.;
MVP		0.53
MPC		0.029
ClinPred		0.75	D
GERP RS		3.9
Varity_R		0.12
gMVP		0.65

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

No publications associated with this variant yet.

Other links and lift over

hg19: chr16-75573944;