Hb Milano [α109(G16)Leu→Pro (CG>CG); : c.329T>C]: A Novel Variant on the α1-Globin Gene in an Italian Family.

Interest in α-globin point mutations has increased in the past few years because nondeletional variations can affect protein function and stability, giving rise to hemoglobin (Hb) variants that present a wide spectrum of phenotypes, from asymptomatic forms to hemolytic anemia. We describe a novel α1-globin gene variant, which we have named Hb Milano [α109(G16)Leu→Pro (CG>CG); : c.329T>C]. We performed high performance liquid chromatography (HPLC) to carry out Hb analysis, capillary electrophoresis (CE) for Hb separation and quantitation of Hb subtypes, two tests on stroma-free lysates for evaluating Hb stability, multiplex ligation-dependent probe amplification (MLPA) to detect deletions/duplications within the α gene cluster and Sanger sequencing of the α-globin genes. No abnormal Hb variants were identified by HPLC and CE. Isopropanol and stability tests were negative. The peripheral blood film showed no inclusions such as Hb H or Heinz bodies. Multiplication ligation-dependent probe amplification of the α-globin gene cluster detected a heterozygosity for the -α (rightward) deletion. Direct sequencing of the α-globin genes identified the Hb Milano variant on the gene. No mutations were found on the gene. The clinical consequences of the Hb Milano variant differ based on the genotype: according to our study, the hematological parameters range from a marked microcythemia with mild anemia if the variant is coinherited with an α gene deletion, to mild microcytosis when the variant is not associated with α gene deletions.