2-73385816-C-T

Variant names:

• chr2-73385816-C-T
• rs868088238
• ENST00000484298.5:c.-53C>T

Variant summary

Our verdict is Likely benign. The variant received -2 ACMG points: 2P and 4B. PM2 BP4_Strong

The NM_015120.4(ALMS1):​c.-53C>T variant causes a 5 prime UTR change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000132 in 681,618 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 32)
  • Exomes 𝑓: 0.000015 (0 hom.)
• Consequence: ALMS1 NM_015120.4 5_prime_UTR
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.287
• 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

ENSG00000285068 (HGNC:):

ACMG classification

Our verdict: Likely_benign. The variant received -2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.79).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
ALMS1	NM_015120.4	c.-53C>T		5_prime_UTR_variant	Exon 1 of 23		NP_055935.4
ALMS1	NM_001378454.1	c.-53C>T		upstream_gene_variant		ENST00000613296.6	NP_001365383.1
LOC105374804	XR_007087045.1	n.-135G>A		upstream_gene_variant
LOC105374804	XR_007087053.1	n.-135G>A		upstream_gene_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
ALMS1	ENST00000613296.6	c.-53C>T		upstream_gene_variant		1	NM_001378454.1	ENSP00000482968.1

Frequencies

GnomAD3 genomes AF: 0.00000658 AC: 1 AN: 152076 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

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: 0.0000147

Gnomad OTH AF: 0.00

GnomAD4 exome AF: 0.0000151 AC: 8 AN: 529542 Hom.: 0 Cov.: 4 AF XY: 0.0000105 AC XY: 3 AN XY: 285512

African (AFR) AF: 0.0000675 AC: 1 AN: 14822

American (AMR) AF: 0.00 AC: 0 AN: 31974

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 18214

East Asian (EAS) AF: 0.00 AC: 0 AN: 31350

South Asian (SAS) AF: 0.00 AC: 0 AN: 57452

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 33722

Middle Eastern (MID) AF: 0.000427 AC: 1 AN: 2344

European-Non Finnish (NFE) AF: 0.0000161 AC: 5 AN: 310050

Other (OTH) AF: 0.0000338 AC: 1 AN: 29614

GnomAD4 genome AF: 0.00000658 AC: 1 AN: 152076 Hom.: 0 Cov.: 32 AF XY: 0.0000135 AC XY: 1 AN XY: 74288

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 41438

American (AMR) AF: 0.00 AC: 0 AN: 15266

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3472

East Asian (EAS) AF: 0.00 AC: 0 AN: 5170

South Asian (SAS) AF: 0.00 AC: 0 AN: 4830

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10610

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.0000147 AC: 1 AN: 67968

Other (OTH) AF: 0.00 AC: 0 AN: 2094

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0.000000), which strongly suggests a high chance of mosaicism in these individuals.

Alfa AF: 0.00 Hom.: 0

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Alstrom syndrome Uncertain:1

Jan 13, 2018

Illumina Laboratory Services, Illumina

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.79
CADD	Benign	6.6
DANN	Benign	0.57
PhyloP100		0.29
PromoterAI		0.092	Neutral

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: rs868088238; hg19: chr2-73612944;