chr16-177334-T-TTCA

Variant names:

Variant summary

Our verdict is Likely benign. The variant received -3 ACMG points: 5P and 8B. PM1PM2PM4_SupportingBP6_Very_Strong

The NM_000558.5(HBA1):c.353_355dupTCA(p.Phe118_Thr119insIle) variant causes a disruptive inframe insertion change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000657 in 152,108 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Likely benign (★★).

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000041 ( 0 hom. )

Failed GnomAD Quality Control

Consequence

HBA1
NM_000558.5 disruptive_inframe_insertion

Scores

Not classified

Clinical Significance

Likely benign criteria provided, multiple submitters, no conflicts B:2

Conservation

PhyloP100: 2.83

Publications

0 publications found

Variant links:

Genes affected

HBA1 (HGNC:4823): (hemoglobin subunit alpha 1) The human alpha globin gene cluster located on chromosome 16 spans about 30 kb and includes seven loci: 5'- zeta - pseudozeta - mu - pseudoalpha-1 - alpha-2 - alpha-1 - theta - 3'. The alpha-2 (HBA2) and alpha-1 (HBA1) coding sequences are identical. These genes differ slightly over the 5' untranslated regions and the introns, but they differ significantly over the 3' untranslated regions. Two alpha chains plus two beta chains constitute HbA, which in normal adult life comprises about 97% of the total hemoglobin; alpha chains combine with delta chains to constitute HbA-2, which with HbF (fetal hemoglobin) makes up the remaining 3% of adult hemoglobin. Alpha thalassemias result from deletions of each of the alpha genes as well as deletions of both HBA2 and HBA1; some nondeletion alpha thalassemias have also been reported. [provided by RefSeq, Jul 2008]

HBA1 Gene-Disease associations (from GenCC):

alpha thalassemia spectrum
Inheritance: AR, SD Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics
erythrocytosis, familial, 7
Inheritance: AD Classification: STRONG Submitted by: Genomics England PanelApp
hemoglobin M disease
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
Hb Bart's hydrops fetalis
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
hemoglobin H disease
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
methemoglobinemia, alpha type
Inheritance: AD Classification: LIMITED Submitted by: ClinGen
Heinz body anemia
Inheritance: AR Classification: LIMITED Submitted by: Labcorp Genetics (formerly Invitae)

HBA1 links:

ENSG00000294436 (HGNC:):

ENSG00000294436 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -3 ACMG points.

PM1

In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 4 benign, 10 uncertain in NM_000558.5

PM2

Very rare variant in population databases, with high coverage;

PM4

Nonframeshift variant in NON repetitive region in NM_000558.5. Strenght limited to Supporting due to length of the change: 1aa.

BP6

Variant 16-177334-T-TTCA is Benign according to our data. Variant chr16-177334-T-TTCA is described in ClinVar as [Likely_benign]. Clinvar id is 439100.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
HBA1	NM_000558.5 link	c.353_355dupTCA	p.Phe118_Thr119insIle	disruptive_inframe_insertion	Exon 3 of 3	ENST00000320868.9	NP_000549.1	P69905D1MGQ2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
HBA1	ENST00000320868.9 link	c.353_355dupTCA	p.Phe118_Thr119insIle	disruptive_inframe_insertion	Exon 3 of 3	1	NM_000558.5	ENSP00000322421.5		P69905

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152108

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.000193

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.00

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000243

AC:

AN:

246942

AF XY:

0.0000149

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.000329

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

Data not reliable, filtered out with message: AS_VQSR

AF:

0.00000411

AC:

AN:

1461010

Hom.:

Cov.:

AF XY:

0.00000275

AC XY:

AN XY:

726804

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33466

American (AMR)

AF:

0.00

AC:

AN:

44662

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26106

East Asian (EAS)

AF:

0.000126

AC:

AN:

39650

South Asian (SAS)

AF:

0.00

AC:

AN:

86162

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53058

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5766

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

1111792

Other (OTH)

AF:

0.0000166

AC:

AN:

60348

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.500

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152108

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74294

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41434

American (AMR)

AF:

0.00

AC:

AN:

15268

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.000193

AC:

AN:

5176

South Asian (SAS)

AF:

0.00

AC:

AN:

4830

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10614

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

67996

Other (OTH)

AF:

0.00

AC:

AN:

2090

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.475

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.00

Hom.:

Bravo

AF:

0.00000378

ClinVar

Significance: Likely benign

Submissions summary: Benign:2

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not provided

Benign:2

Oct 07, 2024

ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The Hb Phnom Penh variant (HBA1: c.353_355dupTCA; p.Phe118_Thr119insIle, also known as Phe117_Thr118insIle when numbered from the mature protein, rs756774032, HbVar ID: 734) is a stable hemoglobin reported in the literature in multiple hematologically normal heterozygous individuals (see HbVar and references therein). This variant has also been reported in an individual with the â€“SEA alpha globin deletion without exacerbating symptoms (Leung 2006). This variant is reported in ClinVar (Variation ID: 439100) and is found in the East Asian population with an overall allele frequency of 0.04% (7/19796 alleles) in the Genome Aggregation Database. This variant inserts a single isoleucine residue leaving the rest of the protein in-frame. Based on available information, this variant is considered to be likely benign. References: Link to HbVar database: https://globin.bx.psu.edu/hbvar/menu.html Leung RY et al. Molecular diagnosis of a case of Hb Phnom Penh [alpha117(GH5)Phe-I1e-alpha118(H1)Thr (alpha1)]. Hemoglobin. 2006;30(3):397-9. PMID: 16840232. -

Nov 15, 2018

Quest Diagnostics Nichols Institute San Juan Capistrano

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

PhyloP100

2.8

Mutation Taster

=36/64

disease causing

(source)

Splicing

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

Publications

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chr16-177334-T-TTCA

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over