chr4-41746244-C-A

Position:

• chr4-41746244-C-A

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM2

The NM_003924.4(PHOX2B):​c.508G>T​(p.Gly170Cys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,672 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: PHOX2B NM_003924.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 1.98

Genes affected

PHOX2B (HGNC:9143): (paired like homeobox 2B) The DNA-associated protein encoded by this gene is a member of the paired family of homeobox proteins localized to the nucleus. The protein functions as a transcription factor involved in the development of several major noradrenergic neuron populations and the determination of neurotransmitter phenotype. The gene product is linked to enhancement of second messenger-mediated activation of the dopamine beta-hydroylase, c-fos promoters and several enhancers, including cyclic amp-response element and serum-response element. Expansion of a 20 amino acid polyalanine tract in this protein by 5-13 aa has been associated with congenital central hypoventilation syndrome. [provided by RefSeq, Jul 2016]

PHOX2B (HGNC:):

ACMG classification

Verdict is Uncertain_significance. Variant got 2 ACMG points.

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

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
PHOX2B	NM_003924.4	c.508G>T	p.Gly170Cys	missense_variant	3/3	ENST00000226382.4	NP_003915.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
PHOX2B	ENST00000226382.4	c.508G>T	p.Gly170Cys	missense_variant	3/3	1	NM_003924.4	ENSP00000226382.2
PHOX2B	ENST00000510424.2	n.329G>T		non_coding_transcript_exon_variant	3/3	3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461672 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 727162

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: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Haddad syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Mar 20, 2022

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. 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: "Not Available"; Align-GVGD: "Class C25"). This variant has not been reported in the literature in individuals affected with PHOX2B-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces glycine, which is neutral and non-polar, with cysteine, which is neutral and slightly polar, at codon 170 of the PHOX2B protein (p.Gly170Cys). -

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Jan 01, 2023

The p.G170C variant (also known as c.508G>T), located in coding exon 3 of the PHOX2B gene, results from a G to T substitution at nucleotide position 508. The glycine at codon 170 is replaced by cysteine, an amino acid with highly dissimilar properties. This amino acid position is conserved. In addition, the in silico prediction for this alteration is inconclusive. 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	Benign	0.18
BayesDel_addAF	Uncertain	0.099	D
BayesDel_noAF	Benign	-0.10
CADD	Pathogenic	27
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.68	D
Eigen	Uncertain	0.19
Eigen_PC	Benign	0.17
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Benign	0.69	T
M_CAP	Pathogenic	0.49	D
MetaRNN	Uncertain	0.43	T
MetaSVM	Uncertain	0.37	D
MutationAssessor	Benign	1.5	L
PrimateAI	Uncertain	0.74	T
PROVEAN	Benign	-2.3	N
REVEL	Uncertain	0.54
Sift	Uncertain	0.0010	D
Sift4G	Uncertain	0.0060	D
Polyphen		1.0	D
Vest4		0.096
MutPred		0.34		Loss of helix (P = 3e-04);
MVP		0.71
MPC		1.2
ClinPred		0.95	D
GERP RS		3.7
Varity_R		0.57
gMVP		0.81

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: rs775931264; hg19: chr4-41748261;