17-68542277-G-T

Variant names:

• chr17-68542277-G-T
• rs2302235
• NM_017565.4:c.929-112C>A

Variant summary

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

The NM_017565.4(FAM20A):​c.929-112C>A variant causes a intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000996 in 1,003,914 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000010 (0 hom.)
• Consequence: FAM20A NM_017565.4 intron
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 0.493
• Publications: 0 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: Splicing predictors support a deleterious effect. Scorers claiming Pathogenic: max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
FAM20A	NM_017565.4	c.929-112C>A		intron_variant	Intron 6 of 10	ENST00000592554.2	NP_060035.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
FAM20A	ENST00000592554.2	c.929-112C>A		intron_variant	Intron 6 of 10	1	NM_017565.4	ENSP00000468308.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 9.96e-7 AC: 1 AN: 1003914 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 510528

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 23860

American (AMR) AF: 0.00 AC: 0 AN: 34364

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 21724

East Asian (EAS) AF: 0.00 AC: 0 AN: 34422

South Asian (SAS) AF: 0.00 AC: 0 AN: 70408

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 43916

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 4900

European-Non Finnish (NFE) AF: 0.00000138 AC: 1 AN: 725476

Other (OTH) AF: 0.00 AC: 0 AN: 44844

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.000000), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.79
CADD	Benign	22
DANN	Benign	0.73
PhyloP100		0.49

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.59		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.59		Position offset: -2

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

Other links and lift over

dbSNP: rs2302235; hg19: chr17-66538418;