4-41747387-G-T

Variant names:

• chr4-41747387-G-T
• rs748614674
• NM_003924.4:c.391C>A

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PM1 PM2 PP3_Moderate

The NM_003924.4(PHOX2B):​c.391C>A​(p.Leu131Met) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic 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. L131V) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: PHOX2B NM_003924.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 4.82
• Publications: 0 publications found

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 Gene-Disease associations (from GenCC):

• central hypoventilation syndrome, congenital, 1, with or without Hirschsprung disease

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae), ClinGen, G2P
• Haddad syndrome

  Inheritance: AD Classification: DEFINITIVE, SUPPORTIVE Submitted by: Orphanet, ClinGen
• neuroblastoma, susceptibility to, 2

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Ambry Genetics, G2P
• congenital central hypoventilation syndrome

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

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

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 20 uncertain in NM_003924.4
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.872

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
PHOX2B	NM_003924.4	c.391C>A	p.Leu131Met	missense_variant	Exon 2 of 3	ENST00000226382.4	NP_003915.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
PHOX2B	ENST00000226382.4	c.391C>A	p.Leu131Met	missense_variant	Exon 2 of 3	1	NM_003924.4	ENSP00000226382.2
PHOX2B	ENST00000510424.2	n.212C>A		non_coding_transcript_exon_variant	Exon 2 of 3	3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 1457292 Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 725090

African (AFR) AF: 0.00 AC: 0 AN: 33478

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

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39698

South Asian (SAS) AF: 0.00 AC: 0 AN: 86252

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 48952

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5746

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111944

Other (OTH) AF: 0.00 AC: 0 AN: 60364

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Haddad syndrome Uncertain:1

Jul 06, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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: "Probably Damaging"; Align-GVGD: "Class C0"). This variant has not been reported in the literature in individuals affected with PHOX2B-related conditions. This variant is not present in population databases (ExAC no frequency). This sequence change replaces leucine with methionine at codon 131 of the PHOX2B protein (p.Leu131Met). The leucine residue is highly conserved and there is a small physicochemical difference between leucine and methionine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.95
BayesDel_addAF	Pathogenic	0.35	D
BayesDel_noAF	Pathogenic	0.27
CADD	Pathogenic	26
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.86	D
Eigen	Uncertain	0.46
Eigen_PC	Uncertain	0.46
FATHMM_MKL	Pathogenic	0.97	D
LIST_S2	Uncertain	0.90	D
M_CAP	Uncertain	0.21	D
MetaRNN	Pathogenic	0.87	D
MetaSVM	Uncertain	0.31	D
MutationAssessor	Pathogenic	3.2	M
PhyloP100		4.8
PrimateAI	Pathogenic	0.91	D
PROVEAN	Benign	-1.6	N
REVEL	Pathogenic	0.88
Sift	Uncertain	0.0010	D
Sift4G	Uncertain	0.0090	D
Polyphen		1.0	D
Vest4		0.73
MutPred		0.73		Gain of ubiquitination at K134 (P = 0.0773);
MVP		0.92
MPC		2.3
ClinPred		0.97	D
GERP RS		4.7
Varity_R		0.80
gMVP		0.96
Mutation Taster		=20/80	disease causing

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

Other links and lift over

dbSNP: rs748614674; hg19: chr4-41749404;