NM_004260.4:c.1909T>C

Variant names:

• chr8-144514077-A-G
• rs1554899485
• NM_004260.4:c.1909T>C

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 4P and 1B. PM2 PM5 BP4

The NM_004260.4(RECQL4):​c.1909T>C​(p.Phe637Leu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. F637S) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 34)
• Consequence: RECQL4 NM_004260.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.911

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]

ACMG classification

Verdict is Uncertain_significance. Variant got 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr8-144514076-A-G is described in Lovd as [Likely_pathogenic].
• BP4: Computational evidence support a benign effect (MetaRNN=0.27946162).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
RECQL4	NM_004260.4	c.1909T>C	p.Phe637Leu	missense_variant	Exon 12 of 21	ENST00000617875.6	NP_004251.4

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
RECQL4	ENST00000617875.6	c.1909T>C	p.Phe637Leu	missense_variant	Exon 12 of 21	1	NM_004260.4	ENSP00000482313.2
RECQL4	ENST00000621189.4	c.838T>C	p.Phe280Leu	missense_variant	Exon 11 of 20	1		ENSP00000483145.1
RECQL4	ENST00000534626.6	c.277T>C	p.Phe93Leu	missense_variant	Exon 3 of 8	5		ENSP00000477457.1
RECQL4	ENST00000532846.2	c.763T>C	p.Phe255Leu	missense_variant	Exon 8 of 9	5		ENSP00000476551.1

Frequencies

GnomAD3 genomes Cov.: 34

GnomAD4 exome Cov.: 36

GnomAD4 genome Cov.: 34

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Baller-Gerold syndrome Uncertain:1

Jul 22, 2017

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces phenylalanine with leucine at codon 637 of the RECQL4 protein (p.Phe637Leu). The phenylalanine residue is highly conserved and there is a small physicochemical difference between phenylalanine and leucine. This variant is not present in population databases (ExAC no frequency). This variant has not been reported in the literature in individuals with RECQL4-related disease. Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be tolerated, but these predictions have not been confirmed by published functional studies and their clinical significance is uncertain. 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 v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.84
BayesDel_addAF	Uncertain	0.092	D
BayesDel_noAF	Benign	-0.11
CADD	Benign	15
DANN	Benign	0.69
DEOGEN2	Benign	0.011	T;T
FATHMM_MKL	Uncertain	0.81	D
LIST_S2	Benign	0.81	T;D
M_CAP	Benign	0.0038	T
MetaRNN	Benign	0.28	T;T
PrimateAI	Uncertain	0.49	T
Sift4G	Benign	0.74	T;T
Polyphen		0.17	.;B
Vest4		0.44
MVP		0.20
GERP RS		5.4
Varity_R		0.23
gMVP		0.56

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: rs1554899485; hg19: chr8-145739461;