2-85657855-G-A

Variant names:

• chr2-85657855-G-A
• rs115696450
• NM_000542.5:c.*1847C>T

Variant summary

Our verdict is Benign. Variant got -20 ACMG points: 0P and 20B. BP4_Strong BP6_Very_Strong BS1 BS2

The NM_000542.5(SFTPB):​c.*1847C>T variant causes a 3 prime UTR change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00805 in 152,042 control chromosomes in the GnomAD database, including 20 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Benign (★★).

• Frequency:
  • Genomes: 𝑓 0.0081 (20 hom., cov: 32)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: SFTPB NM_000542.5 3_prime_UTR
• Clinical Significance: Benign criteria provided, multiple submitters, no conflicts B:2
• Conservation: PhyloP100: -0.840

Genes affected

SFTPB (HGNC:10801): (surfactant protein B) This gene encodes the pulmonary-associated surfactant protein B (SPB), an amphipathic surfactant protein essential for lung function and homeostasis after birth. Pulmonary surfactant is a surface-active lipoprotein complex composed of 90% lipids and 10% proteins which include plasma proteins and apolipoproteins SPA, SPB, SPC and SPD. The surfactant is secreted by the alveolar cells of the lung and maintains the stability of pulmonary tissue by reducing the surface tension of fluids that coat the lung. The SPB enhances the rate of spreading and increases the stability of surfactant monolayers in vitro. Multiple mutations in this gene have been identified, which cause pulmonary surfactant metabolism dysfunction type 1, also called pulmonary alveolar proteinosis due to surfactant protein B deficiency, and are associated with fatal respiratory distress in the neonatal period. Alternatively spliced transcript variants encoding the same protein have been identified.[provided by RefSeq, Feb 2010]

ACMG classification

Verdict is Benign. Variant got -20 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-1.01).
• BP6: Variant 2-85657855-G-A is Benign according to our data. Variant chr2-85657855-G-A is described in ClinVar as [Benign]. Clinvar id is 337292.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• BS1: Variant frequency is greater than expected in population afr. gnomad4 allele frequency = 0.00805 (1224/152042) while in subpopulation AFR AF= 0.0282 (1170/41428). AF 95% confidence interval is 0.0269. There are 20 homozygotes in gnomad4. There are 560 alleles in male gnomad4 subpopulation. Median coverage is 32. This position pass quality control queck.
• BS2: High Homozygotes in GnomAd4 at 20 AR gene

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SFTPB	NM_000542.5	c.*1847C>T		3_prime_UTR_variant	Exon 11 of 11	ENST00000519937.7	NP_000533.4
SFTPB	NM_198843.3	c.*1020C>T		3_prime_UTR_variant	Exon 12 of 12		NP_942140.3
SFTPB	NM_001367281.1	c.*926C>T		3_prime_UTR_variant	Exon 9 of 9		NP_001354210.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SFTPB	ENST00000519937	c.*1847C>T		3_prime_UTR_variant	Exon 11 of 11	1	NM_000542.5	ENSP00000428719.2
SFTPB	ENST00000393822	c.*1847C>T		3_prime_UTR_variant	Exon 12 of 12	1		ENSP00000377409.4

Frequencies

GnomAD3 genomes AF: 0.00805 AC: 1223 AN: 151924 Hom.: 20 Cov.: 32

Gnomad AFR AF: 0.0283

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00256

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.000193

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000735

Gnomad OTH AF: 0.00431

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 4 Hom.: 0 Cov.: 0 AF XY: 0.00 AC XY: 0 AN XY: 4

Gnomad4 NFE exome AF: 0.00

GnomAD4 genome AF: 0.00805 AC: 1224 AN: 152042 Hom.: 20 Cov.: 32 AF XY: 0.00753 AC XY: 560 AN XY: 74352

Gnomad4 AFR AF: 0.0282

Gnomad4 AMR AF: 0.00256

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.000193

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000735

Gnomad4 OTH AF: 0.00427

Alfa AF: 0.00735 Hom.: 1

Bravo AF: 0.00921

Asia WGS AF: 0.00318 AC: 11 AN: 3478

ClinVar

Significance: Benign

Submissions summary: Benign:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Benign:1

-

Breakthrough Genomics, Breakthrough Genomics

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: not provided

- -

Surfactant metabolism dysfunction, pulmonary, 1 Benign:1

Jan 13, 2018

Illumina Laboratory Services, Illumina

Significance: Benign

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 and internal cut-off values, a variant classified as benign is not then subjected to further curation. The score for this variant resulted in a classification of benign for this disease. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-1.0
CADD	Benign	1.6
DANN	Benign	0.56

Splicing

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs115696450; hg19: chr2-85884978;