rs1555793199

Positions:

• chr18-49837749-TG-T

Variant summary

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

The NM_001080467.3(MYO5B):​c.4905del​(p.Thr1636ProfsTer26) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Pathogenic (★★). Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 33)
• Consequence: MYO5B NM_001080467.3 frameshift
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: -2.50

Genes affected

MYO5B (HGNC:7603): (myosin VB) The protein encoded by this gene, together with other proteins, may be involved in plasma membrane recycling. Mutations in this gene are associated with microvillous inclusion disease. [provided by RefSeq, Sep 2009]

SNHG22 (HGNC:50285): (small nucleolar RNA host gene 22)

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 18-49837749-TG-T is Pathogenic according to our data. Variant chr18-49837749-TG-T is described in ClinVar as [Pathogenic]. Clinvar id is 488385.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
MYO5B	NM_001080467.3	c.4905del	p.Thr1636ProfsTer26	frameshift_variant	37/40	ENST00000285039.12	NP_001073936.1
SNHG22	NR_117096.1	n.41-1524del		intron_variant, non_coding_transcript_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
MYO5B	ENST00000285039.12	c.4905del	p.Thr1636ProfsTer26	frameshift_variant	37/40	1	NM_001080467.3	ENSP00000285039	P1
SNHG22	ENST00000589499.1	n.41-1524del		intron_variant, non_coding_transcript_variant		2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 34

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Congenital microvillous atrophy Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Victorian Clinical Genetics Services, Murdoch Childrens Research Institute

Feb 02, 2022

Based on the classification scheme VCGS_Germline_v1.3.4, this variant is classified as Pathogenic. Following criteria are met: 0102 - Loss of function is a known mechanism of disease in this gene and is associated with diarrhea 2, with microvillus atrophy (MIM#251850). (I) 0106 - This gene is associated with autosomal recessive disease. (I) 0201 - Variant is predicted to cause nonsense-mediated decay (NMD) and loss of protein (premature termination codon is located at least 54 nucleotides upstream of the final exon-exon junction). (SP) 0251 - This variant is heterozygous. (I) 0301 - Variant is absent from gnomAD (both v2 and v3). (SP) 0701 - Other NMD predicted variants comparable to the one identified in this case have very strong previous evidence for pathogenicity (DECIPHER, PMID:33525641). (SP) 0807 - This variant has no previous evidence of pathogenicity. (I) 0905 - No published segregation evidence has been identified for this variant. (I) 1007 - No published functional evidence has been identified for this variant. (I) 1206 - This variant has been shown to be paternally inherited (by trio analysis). (I) -

not provided Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Apr 18, 2023

For these reasons, this variant has been classified as Pathogenic. ClinVar contains an entry for this variant (Variation ID: 488385). This variant has not been reported in the literature in individuals affected with MYO5B-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change creates a premature translational stop signal (p.Thr1636Profs*26) in the MYO5B gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in MYO5B are known to be pathogenic (PMID: 18724368, 20186687). -

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: rs1555793199; hg19: chr18-47364119;