19-41354744-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 4P and 2B. PM1 PM2 BP4_Moderate

The NM_030578.4(B9D2):c.484G>A(p.Gly162Ser) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000889 in 1,461,694 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 16/21 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. G162C) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000089 (0 hom.)
• Consequence: B9D2 NM_030578.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.0210

Genes affected

B9D2 (HGNC:28636): (B9 domain containing 2) This gene encodes a B9 domain protein, which are exclusively found in ciliated organisms. The gene is upregulated during mucociliary differentiation, and the encoded protein localizes to basal bodies and cilia. Disrupting expression of this gene results in ciliogenesis defects. [provided by RefSeq, Oct 2009]

TMEM91 (HGNC:32393): (transmembrane protein 91) Predicted to act upstream of or within hematopoietic progenitor cell differentiation. Predicted to be integral component of membrane. Predicted to be active in intracellular membrane-bounded organelle and membrane. [provided by Alliance of Genome Resources, Apr 2022]

ACMG classification

Verdict is Uncertain_significance. Variant got 2 ACMG points.

• PM1: In a chain B9 domain-containing protein 2 (size 174) in uniprot entity B9D2_HUMAN there are 6 pathogenic changes around while only 2 benign (75%) in NM_030578.4
• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.17425087).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
B9D2	NM_030578.4	c.484G>A	p.Gly162Ser	missense_variant	4/4	ENST00000243578.8
B9D2	XM_011527349.3	c.484G>A	p.Gly162Ser	missense_variant	4/4
B9D2	XM_011527350.3	c.325G>A	p.Gly109Ser	missense_variant	3/3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
B9D2	ENST00000243578.8	c.484G>A	p.Gly162Ser	missense_variant	4/4	1	NM_030578.4	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.0000159 AC: 4 AN: 250866 Hom.: 0 AF XY: 0.00000737 AC XY: 1 AN XY: 135746

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000868

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: 0.00000882

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000889 AC: 13 AN: 1461694 Hom.: 0 Cov.: 32 AF XY: 0.0000110 AC XY: 8 AN XY: 727162

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000671

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: 0.00000809

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000378

ExAC AF: 0.00000824 AC: 1

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

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

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

May 03, 2022

This variant is present in population databases (rs760322583, gnomAD 0.009%). This sequence change replaces glycine, which is neutral and non-polar, with serine, which is neutral and polar, at codon 162 of the B9D2 protein (p.Gly162Ser). This variant has not been reported in the literature in individuals affected with B9D2-related conditions. Algorithms developed to predict the effect of missense changes on protein structure and function output the following: SIFT: "Tolerated"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0". The serine amino acid residue is found in multiple mammalian species, which suggests that this missense change does not adversely affect protein function. 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	0.072
BayesDel_addAF	Benign	-0.36	T
BayesDel_noAF	Benign	-0.56
Cadd	Benign	5.3
Dann	Benign	0.94
DEOGEN2	Benign	0.071	T
Eigen	Benign	-1.3
Eigen_PC	Benign	-1.3
FATHMM_MKL	Benign	0.054	N
LIST_S2	Benign	0.54	T
M_CAP	Benign	0.027	D
MetaRNN	Benign	0.17	T
MetaSVM	Benign	-0.99	T
MutationAssessor	Benign	1.6	L
MutationTaster	Benign	1.0	N;N
PrimateAI	Benign	0.34	T
PROVEAN	Benign	-0.98	N
REVEL	Benign	0.10
Sift	Benign	0.63	T
Sift4G	Benign	0.49	T
Polyphen		0.0030	B
Vest4		0.089
MutPred		0.55		Gain of glycosylation at G162 (P = 0.144);
MVP		0.061
MPC		0.23
ClinPred		0.028	T
GERP RS		-0.68
Varity_R		0.080
gMVP		0.52

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: rs760322583; hg19: chr19-41860649; COSMIC: COSV54683705; COSMIC: COSV54683705;