2-73490746-CTT-CTTT

Variant names:

• chr2-73490746-C-CT
• rs1553409778
• NM_001378454.1:c.8790dupT

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_001378454.1(ALMS1):​c.8790dupT​(p.Glu2931fs) variant causes a frameshift, stop gained change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000205 in 1,461,856 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Likely pathogenic (★★). Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: ALMS1 NM_001378454.1 frameshift, stop_gained
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:2 U:1
• Conservation: PhyloP100: 0.922

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]

ACMG classification

Verdict is Pathogenic. Variant got 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 2-73490746-C-CT is Pathogenic according to our data. Variant chr2-73490746-C-CT is described in ClinVar as [Likely_pathogenic]. Clinvar id is 552865.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
ALMS1	NM_001378454.1	c.8790dupT	p.Glu2931fs	frameshift_variant, stop_gained	Exon 10 of 23	ENST00000613296.6	NP_001365383.1
ALMS1	NM_015120.4	c.8790dupT	p.Glu2931fs	frameshift_variant, stop_gained	Exon 10 of 23		NP_055935.4

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
ALMS1	ENST00000613296.6	c.8790dupT	p.Glu2931fs	frameshift_variant, stop_gained	Exon 10 of 23	1	NM_001378454.1	ENSP00000482968.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1461856 Hom.: 0 Cov.: 33 AF XY: 0.00000413 AC XY: 3 AN XY: 727226

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: 0.0000348

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:2 Uncertain:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Alstrom syndrome Pathogenic:2

Jul 12, 2017

Counsyl

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Feb 04, 2024

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.Glu2932*) 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: 552865). For these reasons, this variant has been classified as Pathogenic. -

not provided Uncertain:1

Sep 16, 2018

Gharavi Laboratory, Columbia University

Significance: Uncertain significance

Review Status: no assertion criteria provided

Collection Method: research

- -

Computational scores

Source: dbNSFP v4.3

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

Publications

LitVar

Other links and lift over

dbSNP: rs1553409778; hg19: chr2-73717873;