Submissions for variant NM_000518.5(HBB):c.217dup (p.Ser73fs)

gnomAD frequency: 0.00001  dbSNP: rs33969853

Total submissions: 9

Submitter	RCV	SCV	Clinical significance	Condition	Last evaluated	Review status	Method	Comment
Quest Diagnostics Nichols Institute San Juan Capistrano	RCV000507557	SCV000601259	pathogenic	not provided	2020-12-30	criteria provided, single submitter	clinical testing	The HBB c.217dup (p.Ser73Lysfs*2) pathogenic variant alters the translational reading frame of the HBB mRNA and causes the premature termination of HBB protein synthesis. This variant has been reported to be associated with beta(0)-thalassemia (PMIDs: 26956563 (2016), 24369358 (2014), 6585831 (1984)).
Women's Health and Genetics/Laboratory Corporation of America, LabCorp	RCV000576855	SCV000697094	pathogenic	beta Thalassemia	2016-08-15	criteria provided, single submitter	clinical testing	Variant summary: The HBB c.217dupA (p.Ser73Lysfs) variant results in a premature termination codon, predicted to cause a truncated or absent HBB protein due to nonsense mediated decay, which are commonly known mechanisms for disease. Truncations downstream of this position have been classified as pathogenic by our laboratory (e.g. p.Gly84fs). One in silico tool predicts a damaging outcome for this variant. Additionally, Cheng_PNAS_1984 reported the absence of beta-globin RNA in erythroid cells of a patient homozygous for this variant. The variant was reported in multiple unrelated BTHAL patients in the literature, and authors all classified the variant as pathogenic. This variant was found in 1/121394 control chromosomes at a frequency of 0.0000082, which does not exceed the estimated maximal expected allele frequency of a pathogenic HBB variant (0.0111803). Taken together, this variant is classified as pathogenic.
Myriad Genetics, Inc.	RCV000576855	SCV001193879	likely pathogenic	beta Thalassemia	2019-12-20	criteria provided, single submitter	clinical testing	NM_000518.4(HBB):c.217dupA(aka p.S73Kfs*2) is classified as likely pathogenic in the context of Hb beta chain-related hemoglobinopathy. Please note that S73Kfs*2 is associated with beta thalassemia and is classified as a beta-zero variant. Sources cited for classification include the following: PMID 6585831. Classification of NM_000518.4(HBB):c.217dupA(aka p.S73Kfs*2) is based on the following criteria: The variant causes a premature termination codon that is expected to be targeted by nonsense-mediated mRNA decay and is observed in an individual with the relevant phenotype. Please note: this variant was assessed in the context of healthy population screening.
Invitae	RCV000507557	SCV001410459	pathogenic	not provided	2024-01-04	criteria provided, single submitter	clinical testing	This sequence change creates a premature translational stop signal (p.Ser73Lysfs*2) in the HBB gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in HBB are known to be pathogenic (PMID: 23637309). This variant is present in population databases (rs606231217, gnomAD 0.01%). This premature translational stop signal has been observed in individual(s) with autosomal recessive beta thalassemia (PMID: 6585831). This variant is also known as c.216_217insA or as an insertion of an A nucleotide between codons 71 and 72. ClinVar contains an entry for this variant (Variation ID: 15419). For these reasons, this variant has been classified as Pathogenic.
ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories	RCV000507557	SCV002058086	pathogenic	not provided	2022-09-06	criteria provided, single submitter	clinical testing	The HBB c.217dupA; p.Ser73LysfsTer2 variant (also known as Ser72fs when numbered from the mature protein or as codon 71/72 (+A); HbVar ID: 869) has been reported in individuals with beta(0) thalassemia, including in a homozygous individual with no detectable HBB mRNA (see HbVar, Cheng 1984). This variant is found on only two chromosomes in the Genome Aggregation Database, indicating it is not a common polymorphism. This variant causes a frameshift by inserting a single nucleotide, so it is predicted to result in a truncated protein or mRNA subject to nonsense-mediated decay. Based on available information, the c.217dupA variant is considered to be pathogenic. References: Link to HbVar database: https://globin.bx.psu.edu/hbvar/menu.html Cheng T et al. beta-Thalassemia in Chinese: use of in vivo RNA analysis and oligonucleotide hybridization in systematic characterization of molecular defects. Proc Natl Acad Sci U S A. 1984; 81(9):2821-5. PMID: 6585831.
Ambry Genetics	RCV002426508	SCV002727311	pathogenic	Inborn genetic diseases	2016-09-02	criteria provided, single submitter	clinical testing	The c.217dupA pathogenic mutation (also known as codons 71/72 insertion A), located in coding exon 2 of the HBB gene, results from a duplication of A at nucleotide position 217, causing a translational frameshift with a predicted alternate stop codon (p.S73Kfs*2). This variant was identified previously in a homozygous individual with beta-thalassemia (Cheng TC et al. Proc. Natl. Acad. Sci. U.S.A., 1984 May;81:2821-5). This alteration is expected to result in loss of function by premature protein truncation or nonsense-mediated mRNA decay. As such, this alteration is interpreted as a disease-causing mutation.
OMIM	RCV000016675	SCV000036945	pathogenic	Beta zero thalassemia	1984-05-01	no assertion criteria provided	literature only
The ITHANET community portal, The Cyprus Institute of Neurology and Genetics	RCV000576855	SCV001244479	pathogenic	beta Thalassemia	2019-11-25	no assertion criteria provided	curation
Natera, Inc.	RCV000576855	SCV002089213	pathogenic	beta Thalassemia	2017-03-17	no assertion criteria provided	clinical testing