19-41354921-G-A

Variant summary

Our verdict is Uncertain significance. Variant got 5 ACMG points: 5P and 0B. PM1 PM2 PP3

The NM_030578.4(B9D2):c.307C>T(p.Pro103Ser) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000248 in 1,613,274 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 Uncertain significance (★). Synonymous variant affecting the same amino acid position (i.e. P103P) has been classified as Likely benign.

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 33)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: B9D2 NM_030578.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 8.60

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 5 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
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.824

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
B9D2	NM_030578.4	c.307C>T	p.Pro103Ser	missense_variant	4/4	ENST00000243578.8
B9D2	XM_011527349.3	c.307C>T	p.Pro103Ser	missense_variant	4/4
B9D2	XM_011527350.3	c.148C>T	p.Pro50Ser	missense_variant	3/3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
B9D2	ENST00000243578.8	c.307C>T	p.Pro103Ser	missense_variant	4/4	1	NM_030578.4	P1

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152208 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.0000654

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

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1461066 Hom.: 0 Cov.: 32 AF XY: 0.00000275 AC XY: 2 AN XY: 726838

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000180

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152208 Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 74350

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.0000654

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00

Bravo AF: 0.00000378

EpiCase AF: 0.000109

EpiControl AF: 0.00

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

Jun 02, 2022

This variant has not been reported in the literature in individuals affected with B9D2-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces proline, which is neutral and non-polar, with serine, which is neutral and polar, at codon 103 of the B9D2 protein (p.Pro103Ser). 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: "Deleterious"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0"). 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	0.22
BayesDel_addAF	Pathogenic	0.22	D
BayesDel_noAF	Uncertain	0.070
Cadd	Pathogenic	28
Dann	Pathogenic	1.0
DEOGEN2	Benign	0.40	T
Eigen	Uncertain	0.66
Eigen_PC	Uncertain	0.59
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Uncertain	0.88	D
M_CAP	Pathogenic	0.29	D
MetaRNN	Pathogenic	0.82	D
MetaSVM	Uncertain	-0.077	T
MutationAssessor	Uncertain	2.6	M
MutationTaster	Benign	1.0	D;D
PrimateAI	Uncertain	0.67	T
PROVEAN	Pathogenic	-7.3	D
REVEL	Pathogenic	0.65
Sift	Pathogenic	0.0	D
Sift4G	Uncertain	0.015	D
Polyphen		1.0	D
Vest4		0.73
MutPred		0.55		Gain of catalytic residue at P103 (P = 0.0038);
MVP		0.79
MPC		0.38
ClinPred		1.0	D
GERP RS		4.0
Varity_R		0.86
gMVP		0.71

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: rs1320885309; hg19: chr19-41860826;