17-68537671-G-C

Variant names:

• chr17-68537671-G-C
• rs139620139
• NM_017565.4:c.1432C>G

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 3P and 0B. PM2 PP3

The NM_017565.4(FAM20A):​c.1432C>G​(p.Arg478Gly) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000205 in 1,461,336 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Synonymous variant affecting the same amino acid position (i.e. R478R) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: FAM20A NM_017565.4 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 1.47
• Publications: 9 publications found

Genes affected

FAM20A (HGNC:23015): (FAM20A golgi associated secretory pathway pseudokinase) This locus encodes a protein that is likely secreted and may function in hematopoiesis. A mutation at this locus has been associated with amelogenesis imperfecta and gingival hyperplasia syndrome. Alternatively spliced transcript variants have been identified. [provided by RefSeq, Aug 2011]

PRKAR1A (HGNC:9388): (protein kinase cAMP-dependent type I regulatory subunit alpha) cAMP is a signaling molecule important for a variety of cellular functions. cAMP exerts its effects by activating the cAMP-dependent protein kinase, which transduces the signal through phosphorylation of different target proteins. The inactive kinase holoenzyme is a tetramer composed of two regulatory and two catalytic subunits. cAMP causes the dissociation of the inactive holoenzyme into a dimer of regulatory subunits bound to four cAMP and two free monomeric catalytic subunits. Four different regulatory subunits and three catalytic subunits have been identified in humans. This gene encodes one of the regulatory subunits. This protein was found to be a tissue-specific extinguisher that down-regulates the expression of seven liver genes in hepatoma x fibroblast hybrids. Mutations in this gene cause Carney complex (CNC). This gene can fuse to the RET protooncogene by gene rearrangement and form the thyroid tumor-specific chimeric oncogene known as PTC2. A nonconventional nuclear localization sequence (NLS) has been found for this protein which suggests a role in DNA replication via the protein serving as a nuclear transport protein for the second subunit of the Replication Factor C (RFC40). Several alternatively spliced transcript variants encoding two different isoforms have been observed. [provided by RefSeq, Jan 2013]

PRKAR1A Gene-Disease associations (from GenCC):

• Acrodysostosis 1 with or without hormone resistance

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: G2P, Labcorp Genetics (formerly Invitae), Ambry Genetics
• acrodysostosis with multiple hormone resistance

  Inheritance: AD Classification: DEFINITIVE, SUPPORTIVE Submitted by: Illumina, Orphanet
• Carney complex, type 1

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: G2P, ClinGen, Ambry Genetics, Labcorp Genetics (formerly Invitae)
• pigmented nodular adrenocortical disease, primary, 1

  Inheritance: AD Classification: STRONG, MODERATE Submitted by: Genomics England PanelApp, Ambry Genetics
• acrodysostosis

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• Carney complex

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• familial atrial myxoma

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• primary pigmented nodular adrenocortical disease

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Uncertain_significance. The variant received 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.836

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_017565.4. 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
	FAM20A	NM_017565.4	MANE Select	c.1432C>G	p.Arg478Gly	missense	Exon 11 of 11	NP_060035.2
	FAM20A	NM_001243746.2		c.1018C>G	p.Arg340Gly	missense	Exon 12 of 12	NP_001230675.1
	FAM20A	NR_027751.2		n.1147C>G		non_coding_transcript_exon	Exon 11 of 11

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	FAM20A	ENST00000592554.2	TSL:1 MANE Select	c.1432C>G	p.Arg478Gly	missense	Exon 11 of 11	ENSP00000468308.1
	FAM20A	ENST00000226094.9	TSL:1	n.1110C>G		non_coding_transcript_exon	Exon 11 of 11
	FAM20A	ENST00000619787.4	TSL:5	c.244C>G	p.Arg82Gly	missense	Exon 4 of 4	ENSP00000481085.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD2 exomes AF: 0.00000401 AC: 1 AN: 249326 AF XY: 0.00000742

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: 0.00000890

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1461336 Hom.: 0 Cov.: 35 AF XY: 0.00000275 AC XY: 2 AN XY: 726902

African (AFR) AF: 0.00 AC: 0 AN: 33474

American (AMR) AF: 0.00 AC: 0 AN: 44666

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26110

East Asian (EAS) AF: 0.00 AC: 0 AN: 39690

South Asian (SAS) AF: 0.00 AC: 0 AN: 86076

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53392

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00000270 AC: 3 AN: 1111782

Other (OTH) AF: 0.00 AC: 0 AN: 60378

GnomAD4 genome Cov.: 33

ExAC AF: 0.00000824 AC: 1

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.45
BayesDel_addAF	Pathogenic	0.35	D
BayesDel_noAF	Pathogenic	0.27
CADD	Uncertain	24
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.61	D
Eigen	Uncertain	0.43
Eigen_PC	Uncertain	0.38
FATHMM_MKL	Uncertain	0.93	D
LIST_S2	Uncertain	0.94	D
M_CAP	Uncertain	0.18	D
MetaRNN	Pathogenic	0.84	D
MetaSVM	Uncertain	-0.079	T
MutationAssessor	Uncertain	2.8	M
PhyloP100		1.5
PrimateAI	Uncertain	0.58	T
Sift4G	Uncertain	0.011	D
Polyphen		1.0	D
Vest4		0.79
MutPred		0.50		Loss of phosphorylation at S480 (P = 0.0927)
MVP		0.88
MPC		0.74
ClinPred		0.96	D
GERP RS		3.7
Varity_R		0.89
gMVP		0.81

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: rs139620139; hg19: chr17-66533812;