17-19343332-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 4P and 4B. PM1 PM2 BP4_Strong

The NM_015681.6(B9D1):c.602G>A(p.Ser201Asn) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000205 in 1,461,856 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. S201R) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: B9D1 NM_015681.6 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 0.0790

Genes affected

B9D1 (HGNC:24123): (B9 domain containing 1) This gene encodes a B9 domain-containing protein, one of several that are involved in ciliogenesis. Alterations in expression of this gene have been found in a family with Meckel syndrome. Meckel syndrome has been associated with at least six different genes. This gene is located within the Smith-Magenis syndrome region on chromosome 17. [provided by RefSeq, Mar 2016]

ACMG classification

Verdict is Uncertain_significance. Variant got 0 ACMG points.

• PM1: In a chain B9 domain-containing protein 1 (size 203) in uniprot entity B9D1_HUMAN there are 17 pathogenic changes around while only 6 benign (74%) in NM_015681.6
• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.03946644).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
B9D1	NM_015681.6	c.602G>A	p.Ser201Asn	missense_variant	7/7	ENST00000261499.11

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
B9D1	ENST00000261499.11	c.602G>A	p.Ser201Asn	missense_variant	7/7	1	NM_015681.6	P1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251410 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135882

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000289

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: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1461856 Hom.: 0 Cov.: 29 AF XY: 0.00 AC XY: 0 AN XY: 727240

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: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

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

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Feb 26, 2021

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 output the following: SIFT: "Tolerated"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0". The asparagine amino acid residue is found in multiple mammalian species, suggesting that this missense change does not adversely affect protein function. These predictions have not been confirmed by published functional studies and their clinical significance is uncertain. This variant has not been reported in the literature in individuals with B9D1-related conditions. This variant is not present in population databases (ExAC no frequency). This sequence change replaces serine with asparagine at codon 201 of the B9D1 protein (p.Ser201Asn). The serine residue is weakly conserved and there is a small physicochemical difference between serine and asparagine. -

Inborn genetic diseases Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Apr 12, 2022

The c.602G>A (p.S201N) alteration is located in exon 7 (coding exon 7) of the B9D1 gene. This alteration results from a G to A substitution at nucleotide position 602, causing the serine (S) at amino acid position 201 to be replaced by an asparagine (N). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.069
BayesDel_addAF	Benign	-0.33	T
BayesDel_noAF	Benign	-0.63
Cadd	Benign	3.4
Dann	Benign	0.43
DEOGEN2	Benign	0.0042	T
Eigen	Benign	-1.4
Eigen_PC	Benign	-1.4
FATHMM_MKL	Benign	0.11	N
LIST_S2	Benign	0.21	T
M_CAP	Benign	0.017	T
MetaRNN	Benign	0.039	T
MetaSVM	Benign	-1.0	T
MutationAssessor	Benign	0.90	L
MutationTaster	Benign	1.0	N;N;N;N;N
PrimateAI	Benign	0.33	T
PROVEAN	Benign	-0.31	N
REVEL	Benign	0.056
Sift	Benign	0.21	T
Sift4G	Benign	0.56	T
Polyphen		0.0	B
Vest4		0.037
MutPred		0.074		Loss of phosphorylation at S201 (P = 0.0203);
MVP		0.18
MPC		0.19
ClinPred		0.017	T
GERP RS		-1.5
Varity_R		0.036
gMVP		0.22

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: rs1310730602; hg19: chr17-19246645;