2-73450917-C-T

Variant names:

• chr2-73450917-C-T
• rs904289501
• NM_001378454.1:c.4390C>T

Variant summary

Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_001378454.1(ALMS1):​c.4390C>T​(p.Gln1464*) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,756 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★). Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: ALMS1 NM_001378454.1 stop_gained
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 1.02
• Publications: 0 publications found

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 Gene-Disease associations (from GenCC):

• Alstrom syndrome

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), ClinGen, PanelApp Australia, G2P, Orphanet, Genomics England PanelApp

ACMG classification

Our verdict: Pathogenic. The variant received 18 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 2-73450917-C-T is Pathogenic according to our data. Variant chr2-73450917-C-T is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 529397.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001378454.1. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	ALMS1	NM_001378454.1	MANE Select	c.4390C>T	p.Gln1464*	stop_gained	Exon 8 of 23	NP_001365383.1
	ALMS1	NM_015120.4		c.4390C>T	p.Gln1464*	stop_gained	Exon 8 of 23	NP_055935.4

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	ALMS1	ENST00000613296.6	TSL:1 MANE Select	c.4390C>T	p.Gln1464*	stop_gained	Exon 8 of 23	ENSP00000482968.1
	ALMS1	ENST00000484298.5	TSL:1	c.4264C>T	p.Gln1422*	stop_gained	Exon 7 of 22	ENSP00000478155.1
	ALMS1	ENST00000684548.1		c.4009C>T	p.Gln1337*	stop_gained	Exon 6 of 21	ENSP00000507421.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461756 Hom.: 0 Cov.: 39 AF XY: 0.00 AC XY: 0 AN XY: 727188

African (AFR) AF: 0.00 AC: 0 AN: 33466

American (AMR) AF: 0.00 AC: 0 AN: 44722

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26120

East Asian (EAS) AF: 0.00 AC: 0 AN: 39698

South Asian (SAS) AF: 0.0000116 AC: 1 AN: 86242

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53412

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5762

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111944

Other (OTH) AF: 0.00 AC: 0 AN: 60390

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Alstrom syndrome Pathogenic:2

Oct 20, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change creates a premature translational stop signal (p.Gln1465*) in the ALMS1 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in ALMS1 are known to be pathogenic (PMID: 17594715). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with ALMS1-related conditions. ClinVar contains an entry for this variant (Variation ID: 529397). For these reasons, this variant has been classified as Pathogenic.

Mar 29, 2022

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

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: ALMS1 c.4387C>T/p.Gln1463X (also known as c.4393C>T/p.Gln1465Ter in RefSeq) results in a premature termination codon, predicted to cause a truncation of the encoded protein or absence of the protein due to nonsense mediated decay, which are commonly known mechanisms for disease. Truncations downstream of this position have been classified as pathogenic by our laboratory. The variant was absent in 249228 control chromosomes. To our knowledge, no occurrence of c.4387C>T in individuals affected with Alstrom Syndrome and no experimental evidence demonstrating its impact on protein function have been reported. One clinical diagnostic laboratory has submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation and classified the variant as pathogenic. Based on the evidence outlined above, the variant was classified as likely pathogenic.

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.35	D
BayesDel_noAF	Pathogenic	0.27
CADD	Pathogenic	32
DANN	Uncertain	0.99
Eigen	Benign	0.14
Eigen_PC	Benign	-0.24
FATHMM_MKL	Benign	0.19	N
PhyloP100		1.0
Vest4		0.80
GERP RS		1.4
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Mutation Taster		=0/200	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		Details are displayed if max score is > 0.2

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

Other links and lift over

dbSNP: rs904289501; hg19: chr2-73678044;