8-144511790-C-T

Variant names:

• chr8-144511790-C-T
• rs752301125
• NM_004260.4:c.3394-1G>A

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PVS1_Moderate PM2 PP5_Moderate

The NM_004260.4(RECQL4):​c.3394-1G>A variant causes a splice acceptor, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000685 in 1,460,062 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 2/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★).

• Frequency:
  • Genomes: not found (cov: 34)
  • Exomes 𝑓: 0.0000068 (0 hom.)
• Consequence: RECQL4 NM_004260.4 splice_acceptor, intron
• Scores: Splicing: ADA: 0.03328
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 2.39
• Publications: 0 publications found

Genes affected

RECQL4 (HGNC:9949): (RecQ like helicase 4) The protein encoded by this gene is a DNA helicase that belongs to the RecQ helicase family. DNA helicases unwind double-stranded DNA into single-stranded DNAs and may modulate chromosome segregation. This gene is predominantly expressed in thymus and testis. Mutations in this gene are associated with Rothmund-Thomson, RAPADILINO and Baller-Gerold syndromes. [provided by RefSeq, Jan 2010]

RECQL4 Gene-Disease associations (from GenCC):

• Baller-Gerold syndrome

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: PanelApp Australia, G2P, Orphanet
• Rothmund-Thomson syndrome

  Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
• Rothmund-Thomson syndrome type 2

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Orphanet, Genomics England PanelApp, G2P
• osteosarcoma

  Inheritance: AR Classification: STRONG Submitted by: Genomics England PanelApp
• rapadilino syndrome

  Inheritance: AR Classification: STRONG, SUPPORTIVE Submitted by: Orphanet, Genomics England PanelApp

ACMG classification

Our verdict: Likely_pathogenic. The variant received 6 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.030052384 fraction of the gene. Cryptic splice site detected, with MaxEntScore 6.1, offset of 6, new splice context is: gcctgtccacacaactccAGgat. Cryptic site results in inframe change. If cryptic site found is not functional and variant results in exon loss, it results in frameshift change.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 8-144511790-C-T is Pathogenic according to our data. Variant chr8-144511790-C-T is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 864618.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
RECQL4	NM_004260.4	c.3394-1G>A		splice_acceptor_variant, intron_variant	Intron 19 of 20	ENST00000617875.6	NP_004251.4

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
RECQL4	ENST00000617875.6	c.3394-1G>A		splice_acceptor_variant, intron_variant	Intron 19 of 20	1	NM_004260.4	ENSP00000482313.2

Frequencies

GnomAD3 genomes Cov.: 34

GnomAD4 exome AF: 0.00000685 AC: 10 AN: 1460062 Hom.: 0 Cov.: 36 AF XY: 0.00000826 AC XY: 6 AN XY: 726296

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

American (AMR) AF: 0.00 AC: 0 AN: 44722

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: 86252

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 51960

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

European-Non Finnish (NFE) AF: 0.00000900 AC: 10 AN: 1111716

Other (OTH) AF: 0.00 AC: 0 AN: 60338

GnomAD4 genome Cov.: 34

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000756

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Baller-Gerold syndrome Pathogenic:1

Aug 11, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. ClinVar contains an entry for this variant (Variation ID: 864618). This variant has not been reported in the literature in individuals affected with RECQL4-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change affects an acceptor splice site in intron 19 of the RECQL4 gene. It is expected to disrupt RNA splicing. Variants that disrupt the donor or acceptor splice site typically lead to a loss of protein function (PMID: 16199547), and loss-of-function variants in RECQL4 are known to be pathogenic (PMID: 12734318, 12952869). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.22	D
BayesDel_noAF	Uncertain	0.080
CADD	Uncertain	24
DANN	Uncertain	0.99
FATHMM_MKL	Uncertain	0.96	D
PhyloP100		2.4
GERP RS		4.1
Mutation Taster		=11/89	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.033
dbscSNV1_RF	Benign	0.23
SpliceAI score (max)		0.99		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.74		Position offset: -7
DS_AL_spliceai		0.99		Position offset: -1

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

Other links and lift over

dbSNP: rs752301125; hg19: chr8-145737173;