Genetic Variant FAM20C:c.1446-1G>C (chr7-258645-G-C) – ACMG Classification: Uncertain_significance (4 pts)

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PVS1_ModeratePM2

The NM_020223.4(FAM20C):c.1446-1G>C variant causes a splice acceptor, intron change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000722 in 1,384,546 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

Frequency

Genomes: not found (cov: 33)

Exomes 𝑓: 7.2e-7 ( 0 hom. )

Consequence

FAM20C
NM_020223.4 splice_acceptor, intron

Scores

Splicing: ADA: 1.000

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: 9.09

Publications

0 publications found

Variant links:

Genes affected

FAM20C (HGNC:22140): (FAM20C golgi associated secretory pathway kinase) This gene encodes a member of the family of secreted protein kinases. The encoded protein binds calcium and phosphorylates proteins involved in bone mineralization. Mutations in this gene are associated with the autosomal recessive disorder Raine syndrome. [provided by RefSeq, Apr 2014]

FAM20C Gene-Disease associations (from GenCC):

lethal osteosclerotic bone dysplasia
Inheritance: AR Classification: DEFINITIVE, STRONG, MODERATE, SUPPORTIVE Submitted by: G2P, Genomics England PanelApp, Orphanet, Labcorp Genetics (formerly Invitae), Ambry Genetics

FAM20C links:

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ACMG classification

Classification was made for transcript

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

PVS1

Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.034188036 fraction of the gene. Cryptic splice site detected, with MaxEntScore 3.7, offset of 49, new splice context is: ccatcctggtgccgctacAGcag. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in inframe change.

PM2

Very rare variant in population databases, with high coverage;

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_020223.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	FAM20C	NM_020223.4	MANE Select	c.1446-1G>C		splice_acceptor intron	N/A	NP_064608.2

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	FAM20C	ENST00000313766.6	TSL:1 MANE Select	c.1446-1G>C		splice_acceptor intron	N/A	ENSP00000322323.5
	FAM20C	ENST00000515795.1	TSL:1	n.1103-1G>C		splice_acceptor intron	N/A

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

7.22e-7

AC:

AN:

1384546

Hom.:

Cov.:

AF XY:

0.00000146

AC XY:

AN XY:

683222

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

31590

American (AMR)

AF:

0.00

AC:

AN:

35676

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

25142

East Asian (EAS)

AF:

0.00

AC:

AN:

35734

South Asian (SAS)

AF:

0.00

AC:

AN:

79228

European-Finnish (FIN)

AF:

0.00

AC:

AN:

35010

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5692

European-Non Finnish (NFE)

AF:

9.27e-7

AC:

AN:

1078594

Other (OTH)

AF:

0.00

AC:

AN:

57880

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.425

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

Cov.:

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Pathogenic

0.63

BayesDel_noAF

Pathogenic

0.22

CADD

Pathogenic

(source)

DANN

Uncertain

0.99

Eigen

Pathogenic

1.0

Eigen_PC

Pathogenic

0.82

FATHMM_MKL

Pathogenic

0.99

PhyloP100

9.1

GERP RS

4.5

Mutation Taster

=1/99

disease causing

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Pathogenic

1.0

dbscSNV1_RF

Pathogenic

0.95

SpliceAI score (max)

0.99

Details are displayed if max score is > 0.2

DS_AG_spliceai

0.43

Position offset: 11

DS_AL_spliceai

0.99

Position offset: 1

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

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

ClinVar

Computational scores

Splicing

Publications

Other links and lift over