10-73228184-G-C

Position:

• chr10-73228184-G-C

Variant summary

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

The NM_173348.2(FAM149B1):​c.1023G>C​(p.Pro341Pro) variant causes a splice region, synonymous change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: FAM149B1 NM_173348.2 splice_region, synonymous
• Scores: Splicing: ADA: 0.9999
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 1.15

Genes affected

FAM149B1 (HGNC:29162): (family with sequence similarity 149 member B1) Involved in cilium assembly and protein localization to cilium. Predicted to be located in cilium. Implicated in Joubert syndrome. [provided by Alliance of Genome Resources, Apr 2022]

FAM149B1 (HGNC:):

ACMG classification

Verdict is Uncertain_significance. Variant got 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
FAM149B1	NM_173348.2	c.1023G>C	p.Pro341Pro	splice_region_variant, synonymous_variant	8/14	ENST00000242505.11	NP_775483.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
FAM149B1	ENST00000242505.11	c.1023G>C	p.Pro341Pro	splice_region_variant, synonymous_variant	8/14	5	NM_173348.2	ENSP00000242505.6

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Jul 11, 2023

Variant summary: FAM149B1 c.1023G>C (p.Pro341Pro) results in a synonymous change to the encoded protein, but alters a non-conserved nucleotide located close to a canonical splice site and therefore could affect mRNA splicing, leading to a significantly altered protein sequence. Several computational tools predict a significant impact on normal splicing: Three predict the variant weakens the canonical 5' donor site and one predicts the variant to have no significant impact on splicing. However, these predictions have yet to be confirmed by functional studies. The variant was absent in 156354 control chromosomes (gnomAD). The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. To our knowledge, no occurrence of c.1023G>C in individuals affected with Joubert Syndrome 36 and no experimental evidence demonstrating its impact on protein function have been reported. No submitters have provided clinical-significance assessments for this variant to ClinVar after 2014. Based on the evidence outlined above, the variant was classified as uncertain significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.34
CADD	Benign	19
DANN	Benign	0.86

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.93
SpliceAI score (max)		0.69		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.69		Position offset: 0

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: chr10-74987942;