rs775975261

Variant names:

• chr4-80201482-C-T
• rs775975261
• NM_001099403.2:c.412C>T

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PM2

The NM_001099403.2(PRDM8):​c.412C>T​(p.Leu138Phe) variant causes a missense change. The variant allele was found at a frequency of 0.0000041 in 1,461,774 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000041 (0 hom.)
• Consequence: PRDM8 NM_001099403.2 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 4.03
• Publications: 0 publications found

Genes affected

PRDM8 (HGNC:13993): (PR/SET domain 8) This gene encodes a protein that belongs to a conserved family of histone methyltransferases that predominantly act as negative regulators of transcription. The encoded protein contains an N-terminal Su(var)3-9, Enhancer-of-zeste, and Trithorax (SET) domain and a double zinc-finger domain. Knockout of this gene in mouse results in mistargeting by neurons of the dorsal telencephalon, abnormal itch-like behavior, and impaired differentiation of rod bipolar cells. In humans, the protein has been shown to interact with the phosphatase laforin and the ubiquitin ligase malin, which regulate glycogen construction in the cytoplasm. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Feb 2016]

PRDM8 Gene-Disease associations (from GenCC):

• early-onset Lafora body disease

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

ACMG classification

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001099403.2. 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
	PRDM8	NM_001099403.2	MANE Select	c.412C>T	p.Leu138Phe	missense	Exon 3 of 4	NP_001092873.1
	PRDM8	NM_020226.4		c.412C>T	p.Leu138Phe	missense	Exon 9 of 10	NP_064611.3

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	PRDM8	ENST00000415738.3	TSL:1 MANE Select	c.412C>T	p.Leu138Phe	missense	Exon 3 of 4	ENSP00000406998.2
	PRDM8	ENST00000339711.8	TSL:1	c.412C>T	p.Leu138Phe	missense	Exon 9 of 10	ENSP00000339764.4
	PRDM8	ENST00000515013.5	TSL:1	c.412C>T	p.Leu138Phe	missense	Exon 9 of 10	ENSP00000425149.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD2 exomes AF: 0.0000200 AC: 5 AN: 249562 AF XY: 0.00

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: 0.0000353

Gnomad OTH exome AF: 0.000165

GnomAD4 exome AF: 0.00000410 AC: 6 AN: 1461774 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 727194

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44720

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26132

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86250

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53420

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

European-Non Finnish (NFE) AF: 0.00000540 AC: 6 AN: 1111922

Other (OTH) AF: 0.00 AC: 0 AN: 60382

GnomAD4 genome Cov.: 33

Alfa AF: 0.0000818 Hom.: 0

Bravo AF: 0.0000113

ExAC AF: 0.00000827 AC: 1

EpiCase AF: 0.0000545

EpiControl AF: 0.00

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Early-onset Lafora body disease Uncertain:1

Feb 20, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces leucine, which is neutral and non-polar, with phenylalanine, which is neutral and non-polar, at codon 138 of the PRDM8 protein (p.Leu138Phe). This variant is present in population databases (rs775975261, gnomAD 0.004%). This variant has not been reported in the literature in individuals affected with PRDM8-related conditions. ClinVar contains an entry for this variant (Variation ID: 475680). 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: "Possibly Damaging"; 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.

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.90
BayesDel_addAF	Uncertain	0.018	T
BayesDel_noAF	Benign	-0.10
CADD	Pathogenic	28
DANN	Uncertain	1.0
DEOGEN2	Benign	0.072	T
Eigen	Uncertain	0.65
Eigen_PC	Uncertain	0.66
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Benign	0.82	T
M_CAP	Uncertain	0.13	D
MetaRNN	Uncertain	0.61	D
MetaSVM	Uncertain	0.51	D
MutationAssessor	Benign	1.7	L
PhyloP100		4.0
PrimateAI	Uncertain	0.75	T
PROVEAN	Uncertain	-2.6	D
REVEL	Uncertain	0.51
Sift	Benign	0.032	D
Sift4G	Pathogenic	0.0	D
Polyphen		1.0	D
Vest4		0.58
MVP		0.96
ClinPred		0.65	D
GERP RS		5.8
Varity_R		0.37
gMVP		0.61
Mutation Taster		=53/47	polymorphism

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.050		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: rs775975261; hg19: chr4-81122636;