chr2-73603304-G-A

Position:

chr2-73603304-G-A

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM2PP3_Moderate

The NM_001378454.1(ALMS1):c.12362G>A(p.Arg4121Gln) variant causes a missense, splice region change. The variant allele was found at a frequency of 0.0000198 in 1,613,962 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 predicting alterations to normal splicing. Variant has been reported in ClinVar as Uncertain significance (★★).

Frequency

Genomes: 𝑓 0.000072 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000014 ( 0 hom. )

Consequence

ALMS1
NM_001378454.1 missense, splice_region

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:7

Conservation

PhyloP100: 6.03

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 Uncertain_significance. Variant got 4 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

PP3

Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
ALMS1	NM_001378454.1 linkuse as main transcript	c.12362G>A	p.Arg4121Gln	missense_variant, splice_region_variant	21/23	ENST00000613296.6	NP_001365383.1
ALMS1	NM_015120.4 linkuse as main transcript	c.12365G>A	p.Arg4122Gln	missense_variant, splice_region_variant	21/23		NP_055935.4

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
ALMS1	ENST00000613296.6 linkuse as main transcript	c.12362G>A	p.Arg4121Gln	missense_variant, splice_region_variant	21/23	1	NM_001378454.1	ENSP00000482968	P3	Q8TCU4-1

Frequencies

GnomAD3 genomes

AF:

0.0000723

AC:

AN:

152126

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.000169

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000588

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000358

AC:

AN:

251232

Hom.:

AF XY:

0.0000442

AC XY:

AN XY:

135822

show subpopulations

Gnomad AFR exome

AF:

0.000186

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.000109

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000352

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000144

AC:

AN:

1461718

Hom.:

Cov.:

AF XY:

0.0000179

AC XY:

AN XY:

727164

show subpopulations

Gnomad4 AFR exome

AF:

0.0000299

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.0000504

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000144

Gnomad4 OTH exome

AF:

0.0000331

GnomAD4 genome

AF:

0.0000723

AC:

AN:

152244

Hom.:

Cov.:

AF XY:

0.0000806

AC XY:

AN XY:

74456

show subpopulations

Gnomad4 AFR

AF:

0.000169

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000588

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.000116

Hom.:

Bravo

AF:

0.000106

ESP6500AA

AF:

0.000227

AC:

ESP6500EA

AF:

0.00

AC:

ExAC

AF:

0.0000330

AC:

EpiCase

AF:

0.00

EpiControl

AF:

0.0000593

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:7

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Alstrom syndrome

Uncertain:4

Uncertain significance, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Oct 05, 2022	This sequence change replaces arginine, which is basic and polar, with glutamine, which is neutral and polar, at codon 4122 of the ALMS1 protein (p.Arg4122Gln). This variant is present in population databases (rs376602261, gnomAD 0.02%). This missense change has been observed in individual(s) with Alstrom syndrome (PMID: 25846608). ClinVar contains an entry for this variant (Variation ID: 551196). Experimental studies and prediction algorithms are not available or were not evaluated, and the functional significance of this variant is currently unknown. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. 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. -
Uncertain significance, criteria provided, single submitter	clinical testing	Counsyl	Mar 24, 2017	- -
Uncertain significance, no assertion criteria provided	clinical testing	Natera, Inc.	Apr 30, 2021	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Fulgent Genetics, Fulgent Genetics	May 11, 2022	- -

not specified

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

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

Dec 04, 2023

Variant summary: ALMS1 c.12359G>A (p.Arg4120Gln) results in a conservative amino acid change located in the ALMS motif (IPR029299) of the encoded protein sequence. Three of five in-silico tools predict a benign effect of the variant on protein function. In addition, this variant disrupts the last nucleotide of exon 21, and therefore can affect splicing. Several computational tools predict a significant impact on normal splicing: one predicts the variant abolishes a 5' splicing donor site. Two predict the variant weakens a 5' donor site. However, these predictions have yet to be confirmed by functional studies. The variant allele was found at a frequency of 3.6e-05 in 251232 control chromosomes (gnomAD). The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. c.12359G>A has been reported in the literature in at least one individual affected with Alstrom Syndrome (e.g., Marshall_2015, Shi_2023), however without strong evidence for causality (e.g., lack of co-occurrence and co-segregation data). These reports therefore 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, 36685911). Six submitters have reported clinical-significance assessments for this variant to ClinVar after 2014. All submitters classified the variant as uncertain significance. Based on the evidence outlined above, the variant was classified as uncertain significance. -

not provided

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Sep 02, 2020

Not observed at a significant frequency in large population cohorts (Lek et al., 2016); In silico analysis, which includes protein predictors and evolutionary conservation, supports that this variant does not alter protein structure/function; In-silico analysis, which includes splice predictors and evolutionary conservation, is inconclusive as to whether the variant alters gene splicing. In the absence of RNA/functional studies, the actual effect of this sequence change is unknown.; This variant is associated with the following publications: (PMID: 25846608) -

Cardiovascular phenotype

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Oct 02, 2023

The p.R4122Q variant (also known as c.12365G>A), located in coding exon 21 of the ALMS1 gene, results from a G to A substitution at nucleotide position 12365. The arginine at codon 4122 is replaced by glutamine, an amino acid with highly similar properties. However, this change occurs in the last base pair of coding exon 21, which makes it likely to have some effect on normal mRNA splicing. This nucleotide position is highly conserved in available vertebrate species. This amino acid position is highly conserved in available vertebrate species. In silico splice site analysis predicts that this alteration may weaken the native splice donor site and will result in the creation or strengthening of a novel splice donor site. In addition, as a missense substitution this alteration is predicted to be tolerated by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.16

BayesDel_addAF

Benign

-0.13

BayesDel_noAF

Benign

-0.14

CADD

Pathogenic

DANN

Pathogenic

1.0

DEOGEN2

Benign

0.045

T;.

Eigen

Uncertain

0.59

Eigen_PC

Uncertain

0.57

FATHMM_MKL

Uncertain

0.92

LIST_S2

Uncertain

0.87

D;D

M_CAP

Benign

0.0062

MetaRNN

Benign

0.36

T;T

MetaSVM

Benign

-1.2

MutationTaster

Benign

0.53

D;D

PrimateAI

Benign

0.37

Sift4G

Uncertain

0.0080

D;D

Vest4

0.57

MVP

0.40

ClinPred

0.59

GERP RS

4.3

Varity_R

0.11

gMVP

0.18

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.82

Details are displayed if max score is > 0.2

DS_DG_spliceai

0.82

Position offset: 20

DS_DL_spliceai

0.48

Position offset: 0

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