3-45827460-C-T

Variant summary

Our verdict is Pathogenic. Variant got 16 ACMG points: 16P and 0B. PVS1 PM2 PP3_Strong PP5_Moderate

The NM_020347.4(LZTFL1):c.778-1G>A variant causes a splice acceptor change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000624 in 1,441,490 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 2/2 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000062 (0 hom.)
• Consequence: LZTFL1 NM_020347.4 splice_acceptor
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 7.50

Genes affected

LZTFL1 (HGNC:6741): (leucine zipper transcription factor like 1) This gene encodes a ubiquitously expressed protein that localizes to the cytoplasm. This protein interacts with Bardet-Biedl Syndrome (BBS) proteins and, through its interaction with BBS protein complexes, regulates protein trafficking to the ciliary membrane. Nonsense mutations in this gene cause a form of Bardet-Biedl Syndrome; a ciliopathy characterized in part by polydactyly, obesity, cognitive impairment, hypogonadism, and kidney failure. This gene may also function as a tumor suppressor; possibly by interacting with E-cadherin and the actin cytoskeleton and thereby regulating the transition of epithelial cells to mesenchymal cells. [provided by RefSeq, Aug 2020]

(HGNC:):

ACMG classification

Verdict is Pathogenic. Variant got 16 ACMG points.

• PVS1: Splicing variant, LoF is a know mechanism of disease, Cryptic splice site detected, with MaxEntScore 5.4, offset of -28, new splice context is: ttccttaactatttttttAGtaa. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in frameshift change.
• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.
• PP5: Variant 3-45827460-C-T is Pathogenic according to our data. Variant chr3-45827460-C-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 1345900.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
LZTFL1	NM_020347.4	c.778-1G>A		splice_acceptor_variant		ENST00000296135.11

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
LZTFL1	ENST00000296135.11	c.778-1G>A		splice_acceptor_variant		1	NM_020347.4	P1
	ENST00000699185.1	n.3796+60C>T		intron_variant, non_coding_transcript_variant

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000399 AC: 1 AN: 250582 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135476

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

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: 0.00000624 AC: 9 AN: 1441490 Hom.: 0 Cov.: 26 AF XY: 0.00000278 AC XY: 2 AN XY: 718500

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: 0.00000640

Gnomad4 OTH exome AF: 0.0000335

GnomAD4 genome Cov.: 32

Alfa AF: 0.0000468 Hom.: 0

ExAC AF: 0.00000824 AC: 1

EpiCase AF: 0.00

EpiControl AF: 0.0000593

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Invitae

Jun 13, 2022

In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. This variant has not been reported in the literature in individuals affected with LZTFL1-related conditions. This variant is present in population databases (rs751242409, gnomAD 0.0009%). This sequence change affects an acceptor splice site in intron 8 of the LZTFL1 gene. It is expected to disrupt RNA splicing. Variants that disrupt the donor or acceptor splice site typically lead to a loss of protein function (PMID: 16199547), and loss-of-function variants in LZTFL1 are known to be pathogenic (PMID: 22510444, 23692385). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.39
Cadd	Pathogenic	33
Dann	Uncertain	1.0
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.98
FATHMM_MKL	Pathogenic	0.99	D
MutationTaster	Benign	1.0	D;D;D
GERP RS		5.0

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
SpliceAI score (max)		0.97		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.47		Position offset: 27
DS_AL_spliceai		0.97		Position offset: -1

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

Publications

LitVar

Other links and lift over

dbSNP: rs751242409; hg19: chr3-45868952;