rs113993990

Variant names:

• chr7-66995297-TC-T
• rs113993990
• NM_016038.4:c.120delG

Variant summary

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

The NM_016038.4(SBDS):​c.120delG​(p.Ser41AlafsTer18) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000657 in 152,204 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Pathogenic (★★). Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 33)
  • Exomes 𝑓: 0.0000041 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: SBDS NM_016038.4 frameshift
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:5 O:1
• Conservation: PhyloP100: 0.597

Genes affected

SBDS (HGNC:19440): (SBDS ribosome maturation factor) This gene encodes a highly conserved protein that plays an essential role in ribosome biogenesis. The encoded protein interacts with elongation factor-like GTPase 1 to disassociate eukaryotic initiation factor 6 from the late cytoplasmic pre-60S ribosomal subunit allowing assembly of the 80S subunit. Mutations within this gene are associated with the autosomal recessive disorder Shwachman-Bodian-Diamond syndrome. This gene has a closely linked pseudogene that is distally located. [provided by RefSeq, Jan 2017]

TYW1 (HGNC:25598): (tRNA-yW synthesizing protein 1 homolog) Wybutosine (yW) is a hypermodified guanosine found in phenylalanine tRNA adjacent to the anticodon that stabilizes codon-anticodon interactions in the ribosome. In yeast, the homolog of this gene is essential for the synthesis of wybutosine. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Dec 2015]

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 7-66995297-TC-T is Pathogenic according to our data. Variant chr7-66995297-TC-T is described in ClinVar as [Pathogenic]. Clinvar id is 265256.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr7-66995297-TC-T is described in Lovd as [Likely_pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SBDS	NM_016038.4	c.120delG	p.Ser41AlafsTer18	frameshift_variant	Exon 1 of 5	ENST00000246868.7	NP_057122.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SBDS	ENST00000246868.7	c.120delG	p.Ser41AlafsTer18	frameshift_variant	Exon 1 of 5	1	NM_016038.4	ENSP00000246868.2

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152204 Hom.: 0 Cov.: 33

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

GnomAD2 exomes AF: 0.00000796 AC: 2 AN: 251248 AF XY: 0.0000147

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000176

Gnomad OTH exome AF: 0.00

GnomAD4 exome Data not reliable, filtered out with message: AS_VQSR AF: 0.00000411 AC: 6 AN: 1461448 Hom.: 0 Cov.: 31 AF XY: 0.00000550 AC XY: 4 AN XY: 727024

Gnomad4 AFR exome AF: 0.00 AC: 0 AN: 33468

Gnomad4 AMR exome AF: 0.00 AC: 0 AN: 44724

Gnomad4 ASJ exome AF: 0.00 AC: 0 AN: 26128

Gnomad4 EAS exome AF: 0.00 AC: 0 AN: 39694

Gnomad4 SAS exome AF: 0.00 AC: 0 AN: 86236

Gnomad4 FIN exome AF: 0.00 AC: 0 AN: 53406

Gnomad4 NFE exome AF: 0.00000540 AC: 6 AN: 1111948

Gnomad4 Remaining exome AF: 0.00 AC: 0 AN: 60346

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152204 Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 74370

Gnomad4 AFR AF: 0.00 AC: 0 AN: 0

Gnomad4 AMR AF: 0.00 AC: 0 AN: 0

Gnomad4 ASJ AF: 0.00 AC: 0 AN: 0

Gnomad4 EAS AF: 0.00 AC: 0 AN: 0

Gnomad4 SAS AF: 0.00 AC: 0 AN: 0

Gnomad4 FIN AF: 0.00 AC: 0 AN: 0

Gnomad4 NFE AF: 0.0000147 AC: 0.0000146968 AN: 0.0000146968

Gnomad4 OTH AF: 0.00 AC: 0 AN: 0

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000378

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:5 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:2

Jun 07, 2016

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.120delG pathogenic variant in the SBDS gene has been reported previously (as c.119delG due to alternate nomenclature) in association with Schwachman-Diamond syndrome (Boocock et al., 2003). The c.120delG variant causes a frameshift starting with codon Serine 41, changes this amino acid to an Alanine residue and creates a premature Stop codon at position 18 of the new reading frame, denoted p.Ser41AlafsX18. This variant is predicted to cause loss of normal protein function either through protein truncation or nonsense-mediated mRNA decay. The c.120delG variant was not observed in approximately 6500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benign variant in these populations. We interpret c.120delG as a pathogenic variant. -

Sep 13, 2022

Genetic Services Laboratory, University of Chicago

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

DNA sequence analysis of the SBDS gene demonstrated a one base pair deletion in exon 1, c.120del. This sequence change results in an amino acid frameshift and creates a premature stop codon 18 amino acids downstream of the change, p.Ser41Alafs*18. This sequence change is predicted to result in an abnormal transcript, which may be degraded, or may lead to the production of a truncated SBDS protein with potentially abnormal function. This sequence change has been described in the gnomAD database in 2 individual which corresponds to a population frequency of 0.0008% ((dbSNP rs1175585213). This pathogenic sequence change has previously been described in individuals with SBDS-related disorders (PMID: 12496757, 24388329). Homozygous or compound heterozygous pathogenic variants in the SBDS gene are associated with Shwachman-Bodian-Diamond Syndrome (SBDS) [OMIM#260400]. Features of SDS include exocrine pancreatic dysfunction, growth failure, skeletal changes and hematologic abnormalities with susceptibility to myelodysplastic syndrome and acute myelogeneous leukemia. One pathogenic variant, c.258+2T>G, has been identified in individuals with aplastic anemia in the heterozygous state (PMID: 17478638). However, further studies are needed to establish the association between heterozygous pathogenic variants in SBDS and aplastic anemia. Clinical correlation is recommended. -

Shwachman-Diamond syndrome 1 Pathogenic:1 Other:1

May 02, 2023

Broad Center for Mendelian Genomics, Broad Institute of MIT and Harvard

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: curation

The heterozygous p.Ser41AlafsTer18 variant in SBDS was identified by our study, in the compound heterozygous state with a pathogenic variant (ClinVar Variation ID: 3196), in one individual with Swachman-Diamond syndrome. This individual also carried a pathogenic variant (ClinVar Variation ID: 3196), however the phase of these variants are unknown at this time. The p.Ser41AlafsTer18 variant in SBDS has been previously reported in at least 5 unrelated individuals with Swachman-Diamond syndrome (PMID: 31475115, PMID: 17539775, PMID: 24388329, PMID: 14984468) but has been identified in 0.002% (2/113580) of European (non-Finnish) chromosomes by the Genome Aggregation Database (gnomAD, http://gnomad.broadinstitute.org; dbSNP ID: rs1175585213). Although this variant has been seen in the general population in a heterozygous state, its frequency is low enough to be consistent with a recessive carrier frequency. These 5 previously reported unrelated individuals were compound heterozygotes who carried a reported pathogenic variant in unknown phase (ClinVar Variation ID: 3196, PMID: 31475115, PMID: 17539775, PMID: 24388329, PMID: 14984468), which increases the likelihood that the p.Ser41AlafsTer18 variant in SBDS is pathogenic. This variant has also been reported in ClinVar (Variation ID: 265256) and has been interpreted as pathogenic by GeneDx, Fulgent Genetics, and University of Chicago Genetic Services Laboratory. This variant is predicted to cause a frameshift, which alters the protein’s amino acid sequence beginning at position 41 and leads to a premature termination codon 18 amino acids downstream. This alteration is then predicted to lead to a truncated or absent protein. Loss of function of the SBDS gene is an established disease mechanism in autosomal recessive Swachman-Diamond syndrome. In summary, this variant meets criteria to be classified as pathogenic for autosomal recessive Swachman-Diamond syndrome. ACMG/AMP Criteria applied: PVS1, PM3_Strong, PM2_Supporting (Richards 2015). -

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GeneReviews

Significance: not provided

Review Status: no classification provided

Collection Method: literature only

- -

Aplastic anemia Pathogenic:1

Jul 15, 2023

Baylor Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Aplastic anemia;C4692625:Shwachman-Diamond syndrome 1 Pathogenic:1

Apr 19, 2022

Fulgent Genetics, Fulgent Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
Mutation Taster		=1/199	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

Publications

LitVar

Other links and lift over

dbSNP: rs113993990; hg19: chr7-66460284;