Case Report: Hemoglobin Hasharon with Concurrent Alpha Thalassemia in a Patient with Maple Syrup Urine Disease

Abstract Hemoglobin Hasharon (Hb Hasharon) is an unstable hemoglobin variant stemming from a mutation in the alpha globin gene. This mutation involves the replacement of aspartic acid with histidine at position 47 of the alpha globin chain. Initially identified in 1967 in Israel, Hb Hasharon has since been sporadically reported in various populations, including in Italy, Greece, Germany, and among Latin Americans of Mediterranean descent. Only three English articles have reported several cases of the combined alpha thalassemia deletion and Hasharon mutation, all between 1978-1980. Notably, there has been no prior report of Hb Hasharon with concurrent alpha thalassemia in patients with maple syrup urine disease (MSUD). We hereby present the first case of Hb Hasharon with alpha thalassemia in a patient diagnosed with MSUD. This patient, a 16-month-old female, received a prenatal diagnosis of MSUD through amniocentesis, confirming homozygosity for a known pathogenic variant in DBT (c.75_76delAT, p.C26wfsX2). Prompt initiation of formula feeding has effectively controlled her MSUD. The patient was referred for further evaluation due to hemoglobin newborn screen showing hemoglobin A, Hb F and “variant hemoglobin”. Her parents denied any family history of hemoglobinopathy. Her complete blood count was predominantly normal except for mild microcytosis, with a mean corpuscular volume of 69.1 fl (normal range 70.0-86.0 fl). The patient didn’t exhibit neonatal jaundice or any other signs or symptoms of hemolysis. The reticulocyte count was also within normal limits. The hemoglobin electrophoresis results revealed a complex pattern, with 28.8% of an unknown hemoglobin between zone 4 and 5 on capillary zone electrophoresis (CZE) as well as a possible A2 variant in zone 1. High-performance liquid chromatography (HPLC) indicated a 29.1% peak at a retention time of 4.72 minutes, along with several smaller peaks, that were indicative of the degradation of the unstable unknown hemoglobin. Although the zones and retention time aligned with Hb Hasharon, the percentage differed from the expected range of 19-20% in CZE and 18-21% in HPLC for this variant, prompting the team to order alpha and beta globin sequencing tests. Beta globin gene complete sequencing yielded negative results, while the sequencing of alpha globin gene revealed that the patient carries one copy of the -alpha3.7 alpha-globin deletion and one copy of the c.142G>C (p.Asp48His) variant in the alpha2-globin (HBA2) gene, resulting in an -alpha/alpha2alpha1 genotype with Hb Hasharon. While Hb Hasharon is generally not clinically significant, its co-occurrence with alpha-thalassemia can lead to hemolytic anemia. In our patient, clinic and chemical parameters were predominantly within normal ranges, except for mild microcytosis. The potential interaction between MSUD and Hb Hasharon with concurrent alpha thalassemia remains unknown. Continued patient monitoring will enable us to evaluate whether these conditions may influence each other’s clinical and biochemical profiles.