17-68528878-G-C

Position:

• chr17-68528878-G-C

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 5P and 1B. PM1 PP2 PP3_Moderate BS2_Supporting

The NM_002734.5(PRKAR1A):​c.778G>C​(p.Asp260His) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000372 in 1,613,798 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 13/21 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 33)
  • Exomes 𝑓: 0.0000034 (0 hom.)
• Consequence: PRKAR1A NM_002734.5 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 10.0

Genes affected

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]

ACMG classification

Verdict is Uncertain_significance. Variant got 4 ACMG points.

• PM1: In a binding_site (size 126) in uniprot entity KAP0_HUMAN there are 7 pathogenic changes around while only 0 benign (100%) in NM_002734.5
• PP2: Missense variant in gene, where missense usually causes diseases (based on misZ statistic), PRKAR1A. . Gene score misZ 3.1236 (greater than the threshold 3.09). Trascript score misZ 4.1467 (greater than threshold 3.09). GenCC has associacion of gene with acrodysostosis with multiple hormone resistance, pigmented nodular adrenocortical disease, primary, 1, primary pigmented nodular adrenocortical disease, acrodysostosis, Carney complex, Acrodysostosis 1 with or without hormone resistance, Carney complex, type 1, familial atrial myxoma.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.895
• BS2: High AC in GnomAdExome4 at 5 AD gene. Variant has AC lower than other variant known as pathogenic in the gene, so the strength is limited to Supporting.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
PRKAR1A	NM_002734.5	c.778G>C	p.Asp260His	missense_variant	9/11	ENST00000589228.6	NP_002725.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
PRKAR1A	ENST00000589228.6	c.778G>C	p.Asp260His	missense_variant	9/11	1	NM_002734.5	ENSP00000464977	P1

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152202 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000147

Gnomad OTH AF: 0.00

GnomAD4 exome AF: 0.00000342 AC: 5 AN: 1461596 Hom.: 0 Cov.: 33 AF XY: 0.00000275 AC XY: 2 AN XY: 727108

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000450

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152202 Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 74362

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000147

Gnomad4 OTH AF: 0.00

Bravo AF: 0.00000756

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Carney complex, type 1 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Feb 19, 2022

ClinVar contains an entry for this variant (Variation ID: 469076). This variant has not been reported in the literature in individuals affected with PRKAR1A-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces aspartic acid, which is acidic and polar, with histidine, which is basic and polar, at codon 260 of the PRKAR1A protein (p.Asp260His). Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0"). In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Mar 16, 2022

The p.D260H variant (also known as c.778G>C), located in coding exon 8 of the PRKAR1A gene, results from a G to C substitution at nucleotide position 778. The aspartic acid at codon 260 is replaced by histidine, an amino acid with similar properties. This amino acid position is conserved. In addition, this alteration is predicted to be deleterious by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.76
BayesDel_addAF	Pathogenic	0.49	D
BayesDel_noAF	Pathogenic	0.47
CADD	Pathogenic	31
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.85	D;D;D;D;.;D;.
Eigen	Pathogenic	0.98
Eigen_PC	Pathogenic	0.95
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.96	.;D;.;.;D;.;D
M_CAP	Pathogenic	0.57	D
MetaRNN	Pathogenic	0.89	D;D;D;D;D;D;D
MetaSVM	Pathogenic	0.88	D
MutationAssessor	Pathogenic	3.6	H;H;H;H;.;H;H
MutationTaster	Benign	1.0	D;D;D;D;D
PrimateAI	Pathogenic	0.91	D
PROVEAN	Pathogenic	-5.3	D;D;.;D;.;.;.
REVEL	Pathogenic	0.79
Sift	Uncertain	0.0010	D;D;.;D;.;.;.
Sift4G	Uncertain	0.0040	D;D;D;D;D;D;D
Polyphen		0.97	D;D;D;D;.;D;.
Vest4		0.87
MutPred		0.37		Loss of helix (P = 0.079);Loss of helix (P = 0.079);Loss of helix (P = 0.079);Loss of helix (P = 0.079);Loss of helix (P = 0.079);Loss of helix (P = 0.079);Loss of helix (P = 0.079);
MVP		0.93
MPC		1.6
ClinPred		1.0	D
GERP RS		5.9
Varity_R		0.88
gMVP		0.80

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

Publications

LitVar

Other links and lift over

dbSNP: rs1255519868; hg19: chr17-66525019;