chr2-73559026-TGAA-T

Position:

• chr2-73559026-TGAA-T

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM2 PM4_Supporting

The NM_001378454.1(ALMS1):​c.10272_10274del​(p.Lys3424del) variant causes a inframe deletion change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,792 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: ALMS1 NM_001378454.1 inframe_deletion
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:5
• Conservation: PhyloP100: 1.99

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 Uncertain_significance. Variant got 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM4: Nonframeshift variant in NON repetitive region in NM_001378454.1. Strenght limited to Supporting due to length of the change: 1aa.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
ALMS1	NM_001378454.1	c.10272_10274del	p.Lys3424del	inframe_deletion	15/23	ENST00000613296.6
ALMS1	NM_015120.4	c.10275_10277del	p.Lys3425del	inframe_deletion	15/23

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
ALMS1	ENST00000613296.6	c.10272_10274del	p.Lys3424del	inframe_deletion	15/23	1	NM_001378454.1	P3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461792 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 727194

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: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

Alfa AF: 0.0000712 Hom.: 0

Bravo AF: 0.00000756

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:5

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Alstrom syndrome Uncertain:4

Uncertain significance, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Apr 28, 2022	This variant, c.10275_10277del, results in the deletion of 1 amino acid(s) of the ALMS1 protein (p.Lys3425del), but otherwise preserves the integrity of the reading frame. This variant is present in population databases (no rsID available, gnomAD 0.007%). 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: 550778). Experimental studies and prediction algorithms are not available or were not evaluated, and the functional significance of this variant is currently unknown. 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	Fulgent Genetics, Fulgent Genetics	Oct 28, 2021	- -
Uncertain significance, no assertion criteria provided	clinical testing	Natera, Inc.	May 20, 2021	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Counsyl	Feb 21, 2017	- -

Cardiovascular phenotype Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

May 27, 2020

The c.10275_10277delGAA variant (also known as p.K3425del), located in coding exon 15 of the ALMS1 gene, results from an in-frame GAA deletion at nucleotide positions 10275 to 10277. This results in the in-frame deletion of a lysine at codon 3425. This amino acid position is poorly conserved in available vertebrate species. In addition, this alteration is predicted to be inconclusive by in silico analysis (Choi Y et al. PLoS ONE. 2012; 7(10):e46688). Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

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: rs1184260245; hg19: chr2-73786153;