2-85663779-C-G

Variant names:

• chr2-85663779-C-G
• rs727503418
• NM_000542.5:c.741G>C

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PM1 PM2

The NM_000542.5(SFTPB):​c.741G>C​(p.Gln247His) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000657 in 152,208 control chromosomes in the GnomAD database, with no homozygous occurrence. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Synonymous variant affecting the same amino acid position (i.e. Q247Q) has been classified as Likely benign.

• Frequency: Genomes: 𝑓 0.0000066 (0 hom., cov: 32)
• Consequence: SFTPB NM_000542.5 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 2.58
• Publications: 0 publications found

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]

SFTPB Gene-Disease associations (from GenCC):

• surfactant metabolism dysfunction, pulmonary, 1

  Inheritance: AR Classification: STRONG, SUPPORTIVE Submitted by: Genomics England PanelApp, Orphanet, Labcorp Genetics (formerly Invitae)

ACMG classification

Our verdict: Uncertain_significance. The variant received 4 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 3 uncertain in NM_000542.5
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SFTPB	NM_000542.5	c.741G>C	p.Gln247His	missense_variant	Exon 7 of 11	ENST00000519937.7	NP_000533.4

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SFTPB	ENST00000519937.7	c.741G>C	p.Gln247His	missense_variant	Exon 7 of 11	1	NM_000542.5	ENSP00000428719.2

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152208 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: 0.000193

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD4 exome Cov.: 36

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152208 Hom.: 0 Cov.: 32 AF XY: 0.0000134 AC XY: 1 AN XY: 74352

⚠️ 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: 41454

American (AMR) AF: 0.00 AC: 0 AN: 15286

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

East Asian (EAS) AF: 0.000193 AC: 1 AN: 5194

South Asian (SAS) AF: 0.00 AC: 0 AN: 4834

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10620

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

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 68028

Other (OTH) AF: 0.00 AC: 0 AN: 2092

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000756

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.42
BayesDel_addAF	Uncertain	0.082	D
BayesDel_noAF	Benign	-0.12
CADD	Benign	22
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.68	D;D;T
Eigen	Benign	0.064
Eigen_PC	Benign	0.13
FATHMM_MKL	Benign	0.59	D
LIST_S2	Benign	0.67	.;T;T
M_CAP	Benign	0.031	D
MetaRNN	Uncertain	0.65	D;D;D
MetaSVM	Benign	-0.92	T
MutationAssessor	Benign	0.75	N;N;.
PhyloP100		2.6
PrimateAI	Benign	0.48	T
PROVEAN	Uncertain	-2.6	.;.;D
REVEL	Uncertain	0.54
Sift	Benign	0.091	.;.;T
Sift4G	Benign	0.19	T;T;T
Polyphen		0.82	P;P;P
Vest4		0.65
MutPred		0.64		.;.;Loss of helix (P = 0.2271);
MVP		0.89
MPC		0.60
ClinPred		0.94	D
GERP RS		3.4
PromoterAI		0.0028	Neutral
Varity_R		0.20
gMVP		0.60
Mutation Taster		=72/28	polymorphism

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: rs727503418; hg19: chr2-85890902;