ClinVar Miner

Submissions for variant NM_000518.4(HBB):c.371C>A (p.Thr124Asn)

gnomAD frequency: 0.00001  dbSNP: rs33935383
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Total submissions: 4
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Submitter RCV SCV Clinical significance Condition Last evaluated Review status Method Comment
Genome-Nilou Lab RCV001563767 SCV001786788 uncertain significance beta Thalassemia 2021-07-14 criteria provided, single submitter clinical testing
Women's Health and Genetics/Laboratory Corporation of America, LabCorp RCV001778656 SCV002014920 uncertain significance not specified 2024-01-31 criteria provided, single submitter clinical testing Variant summary: HBB c.371C>A (p.Thr124Asn) results in a non-conservative amino acid change located in the Globin domain (IPR000971) of the encoded protein sequence. Three of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 8e-06 in 251294 control chromosomes (gnomAD). The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. c.371C>A (also known in the literature as Hb Ernz) has been reported in one polycythemic individual but it was also reported in two of his daughters who displayed normal RBC parameters (Groff_2000). Furthermore, the variant was detected in compound heterozygosity with Hb S in 3 siblings that were clinically and hematologically normal, with the authors concluding that it is a silent Hb variant not causing any pathology (Gunesacar_2012). In addition, c.371C>A was detected in an Italian child compound heterozygous for a pathogenic variant (c.118C>T, p.Gln40X) with clinical presentation similar to a beta thal trait (HbVar database) as well as an individual homozygous for Hb Ernz with borderline hematological parameters and a co-occurring 3.7kb deletion of the alpha-globin gene cluster (e.g., Shojaei_2024). Multiple other studies have reported the variant in carrier individuals (e.g. Giambona_2008, Alibakhshi_2019, Arpaci_2021). In several of these publications, the authors suggest the variant represents a benign/neutral polymorphism (e.g., Groff_2000, Gunesacar_2012, Fouladi_2007, Shojaei_2024). To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publications have been ascertained in the context of this evaluation (PMID: 31096791, 33851260, 32126744, 18603555, 11186258, 37826942). ClinVar contains an entry for this variant (Variation ID: 15584). Based on the evidence outlined above, the variant was classified as VUS-possibly benign.
Fulgent Genetics, Fulgent Genetics RCV002482877 SCV002792108 uncertain significance Dominant beta-thalassemia; Heinz body anemia; Hb SS disease; alpha Thalassemia; Malaria, susceptibility to; METHEMOGLOBINEMIA, BETA TYPE; Erythrocytosis, familial, 6; Hereditary persistence of fetal hemoglobin; Beta-thalassemia HBB/LCRB 2022-04-08 criteria provided, single submitter clinical testing
OMIM RCV000016851 SCV000037121 other HEMOGLOBIN ERNZ 2017-12-12 no assertion criteria provided literature only

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