2-73419118-T-G

Position:

chr2-73419118-T-G

Variant summary

Our verdict is Benign. Variant got -7 ACMG points: 2P and 9B. PM2BP4_StrongBP6BS1

The NM_001378454.1(ALMS1):c.451-5T>G variant causes a splice region, splice polypyrimidine tract, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000961 in 1,612,088 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 1/1 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.000079 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000098 ( 0 hom. )

Consequence

ALMS1
NM_001378454.1 splice_region, splice_polypyrimidine_tract, intron

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1B:4

Conservation

PhyloP100: 2.40

Variant links:

Genes affected

ALMS1 (HGNC:428): (ALMS1 centrosome and basal body associated protein) This gene encodes a protein containing a large tandem-repeat domain as well as additional low complexity regions. The encoded protein functions in microtubule organization, particularly in the formation and maintanance of cilia. Mutations in this gene cause Alstrom syndrome. There is a pseudogene for this gene located adjacent in the same region of chromosome 2. Alternative splice variants have been described but their full length nature has not been determined. [provided by RefSeq, Apr 2014]

ALMS1 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Benign. Variant got -7 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.74).

BP6

Variant 2-73419118-T-G is Benign according to our data. Variant chr2-73419118-T-G is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 529408.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=3, Uncertain_significance=1}.

BS1

Variant frequency is greater than expected in population eas. gnomad4 allele frequency = 0.0000788 (12/152336) while in subpopulation EAS AF= 0.00231 (12/5184). AF 95% confidence interval is 0.00134. There are 0 homozygotes in gnomad4. There are 6 alleles in male gnomad4 subpopulation. Median coverage is 32. This position pass quality control queck.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
ALMS1	NM_001378454.1 linkuse as main transcript	c.451-5T>G		splice_region_variant, splice_polypyrimidine_tract_variant, intron_variant		ENST00000613296.6	NP_001365383.1
ALMS1	NM_015120.4 linkuse as main transcript	c.451-5T>G		splice_region_variant, splice_polypyrimidine_tract_variant, intron_variant			NP_055935.4

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
ALMS1	ENST00000613296.6 linkuse as main transcript	c.451-5T>G		splice_region_variant, splice_polypyrimidine_tract_variant, intron_variant		1	NM_001378454.1	ENSP00000482968	P3	Q8TCU4-1

Frequencies

GnomAD3 genomes

AF:

0.0000788

AC:

AN:

152218

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00231

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

GnomAD3 exomes

AF:

0.000141

AC:

AN:

248930

Hom.:

AF XY:

0.000178

AC XY:

AN XY:

135066

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00189

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.000165

GnomAD4 exome

AF:

0.0000980

AC:

143

AN:

1459752

Hom.:

Cov.:

AF XY:

0.000102

AC XY:

AN XY:

726286

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00343

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00

Gnomad4 OTH exome

AF:

0.000116

GnomAD4 genome

AF:

0.0000788

AC:

AN:

152336

Hom.:

Cov.:

AF XY:

0.0000805

AC XY:

AN XY:

74512

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00231

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.00

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000434

Hom.:

Bravo

AF:

0.0000680

Asia WGS

AF:

0.000866

AC:

AN:

3478

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:1Benign:4

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Alstrom syndrome

Uncertain:1Benign:2

Likely benign, no assertion criteria provided	clinical testing	Natera, Inc.	Jan 09, 2020	- -
Likely benign, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Jan 18, 2024	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Counsyl	Feb 14, 2018	- -

not specified

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

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

May 15, 2023

Variant summary: ALMS1 c.451-5T>G (also known as c.454-5T>G) alters a 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: Two predict the variant abolishes a canonical 3' acceptor site and two predict the variant weakens the same canonical 3' acceptor site. However, these predictions have yet to be confirmed by functional studies. The variant allele was found at a frequency of 0.00014 in 248930 control chromosomes (gnomAD), predominantly at a frequency of 0.0019 within the East Asian subpopulation in the gnomAD database. The observed variant frequency within East Asian control individuals in the gnomAD database is approximately 1.3 fold of the estimated maximal expected allele frequency for a pathogenic variant in ALMS1 causing Alstrom Syndrome (0.0014), suggesting that the variant may be a benign polymorphism found primarily in populations of East Asian origin. c.451-5T>G has been reported in the literature in individuals affected with Alstrom Syndrome, retinitis pigmentosa and in an individual affected with combined 17 alpha hydroxylase/17,20-lyase deficiency without strong evidence of causality (Marshall_2015, Xu_2016, Zhang_2018). These reports do not provide unequivocal conclusions about association of the variant with Alstrom Syndrome. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publications have been ascertained in the context of this evaluation (PMID: 25846608, 26010121, 29345162). Four ClinVar submitters have assessed the variant since 2014: two have classified the variant as uncertain significance and two as likely benign. Based on the evidence outlined above, the variant was classified as likely benign. -

Cardiovascular phenotype

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Ambry Genetics

May 27, 2023

This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.74

CADD

Benign

DANN

Benign

0.53

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.040

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

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over