2-169487068-G-T

Variant names:

• chr2-169487068-G-T
• rs1054138918
• NM_152384.3:c.143-1G>T

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PVS1_Moderate PM2

The NM_152384.3(BBS5):​c.143-1G>T variant causes a splice acceptor, intron change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000206 in 1,456,460 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: BBS5 NM_152384.3 splice_acceptor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 7.27
• Publications: 0 publications found

Genes affected

BBS5 (HGNC:970): (Bardet-Biedl syndrome 5) This gene encodes a protein that has been directly linked to Bardet-Biedl syndrome. The primary features of this syndrome include retinal dystrophy, obesity, polydactyly, renal abnormalities and learning disabilities. Experimentation in non-human eukaryotes suggests that this gene is expressed in ciliated cells and that it is required for the formation of cilia. Alternate transcriptional splice variants have been observed but have not been fully characterized. [provided by RefSeq, Jul 2008]

BBS5 Gene-Disease associations (from GenCC):

• Bardet-Biedl syndrome 5

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Genomics England PanelApp, Ambry Genetics, Labcorp Genetics (formerly Invitae), Laboratory for Molecular Medicine, G2P
• BBS5-related ciliopathy

  Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
• Bardet-Biedl syndrome

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ENSG00000251569 (HGNC:):

ACMG classification

Our verdict: Uncertain_significance. The variant received 4 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.064327486 fraction of the gene. Cryptic splice site detected, with MaxEntScore 7.4, offset of 4, new splice context is: gtctgtgtgcttttatgtAGact. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in inframe change.
• PM2: Very rare variant in population databases, with high coverage

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_152384.3. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	BBS5	NM_152384.3	MANE Select	c.143-1G>T		splice_acceptor intron	N/A	NP_689597.1	A0A0S2Z626

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	BBS5	ENST00000295240.8	TSL:1 MANE Select	c.143-1G>T		splice_acceptor intron	N/A	ENSP00000295240.3	Q8N3I7-1
	ENSG00000251569	ENST00000513963.1	TSL:2	c.143-1G>T		splice_acceptor intron	N/A	ENSP00000424363.1	E9PBE3
	BBS5	ENST00000392663.6	TSL:1	c.143-1G>T		splice_acceptor intron	N/A	ENSP00000376431.2	Q8N3I7-2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000206 AC: 3 AN: 1456460 Hom.: 0 Cov.: 29 AF XY: 0.00000276 AC XY: 2 AN XY: 724924

African (AFR) AF: 0.00 AC: 0 AN: 33322

American (AMR) AF: 0.00 AC: 0 AN: 44716

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26082

East Asian (EAS) AF: 0.00 AC: 0 AN: 39548

South Asian (SAS) AF: 0.00 AC: 0 AN: 86138

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53270

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5728

European-Non Finnish (NFE) AF: 0.00000271 AC: 3 AN: 1107464

Other (OTH) AF: 0.00 AC: 0 AN: 60192

GnomAD4 genome Cov.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.45	D
BayesDel_noAF	Pathogenic	0.41
CADD	Pathogenic	34
DANN	Uncertain	1.0
Eigen	Pathogenic	1.3
Eigen_PC	Pathogenic	1.1
FATHMM_MKL	Pathogenic	1.0	D
PhyloP100		7.3
GERP RS		5.7
Mutation Taster		=0/100	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.94
SpliceAI score (max)		0.62		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.30		Position offset: 5
DS_AL_spliceai		0.62		Position offset: 1

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs1054138918; hg19: chr2-170343578;