Related Experiment Video
Updated: Feb 26, 2026

Identification and Classification of Position-specific GABAA Receptor Subunit Missense Variants for Their Role In Hippocampal Pyramidal Neurons
Published on: June 6, 2025
Hb Amsterdam-A1 [α32(B13)Met→Ile; HBA1: c.99G>A]: A Hyperunstable Variant Due to a New Mutation on the α1 Gene
Stephen O Brennan1,2, Darrell Wang2, Mark Horridge2
1a Molecular Pathology Laboratory , University of Otago , Christchurch , New Zealand.
Patients with hyperunstable α chain variants usually present with a thalassemic, rather than hemolytic, phenotype. Electrophoretic, ion exchange and reverse phase separations usually fail to detect the variant and when DNA sequencing identifies a 'silent' substitution it is usually presumed to be hyperunstable. We report the identification of such a variant, α32(B13)Met→Ile; HBA1: c.99G>A, arising from a new mutation on the α1 gene. The hemoglobin (Hb) was unequivocally detected by the isopropanol stability test and confirmed as hyperunstable by mass spectrometry (MS) of the precipitate and lysate, which showed proportions of 55% and 2.5% of α chains, respectively. The instability appears to be driven by perturbation of globin-heme, and possibly α1β1 subunit, interactions.
Patients with hyperunstable α chain variants usually present with a thalassemic, rather than hemolytic, phenotype. Electrophoretic, ion exchange and reverse phase separations usually fail to detect the variant and when DNA sequencing identifies a 'silent' substitution it is usually presumed to be hyperunstable. We report the identification of such a variant, α32(B13)Met→Ile; HBA1: c.99G>A, arising from a new mutation on the α1 gene. The hemoglobin (Hb) was unequivocally detected by the isopropanol stability test and confirmed as hyperunstable by mass spectrometry (MS) of the precipitate and lysate, which showed proportions of 55% and 2.5% of α chains, respectively. The instability appears to be driven by perturbation of globin-heme, and possibly α1β1 subunit, interactions.
More Related Videos
09:34Targeted Next-generation Sequencing and Bioinformatics Pipeline to Evaluate Genetic Determinants of Constitutional Disease
Published on: April 4, 2018
07:26High-resolution Melting PCR for Complement Receptor 1 Length Polymorphism Genotyping: An Innovative Tool for Alzheimer's Disease Gene Susceptibility Assessment
Published on: July 18, 2017
Related Concept Videos
Alternative RNA Splicing
There are five types of alternative RNA splicing that vary in the ways the pre-mRNA segments are removed or retained in the mature mRNA. The first...
Point and Frameshift Mutations
Pharmacogenetics of Drug Targets: β₂-Adrenergic Receptors, Apo E, Thymidylate Synthase
Mutations
Chromosomal Alterations Are Large-Scale Mutations
While point mutations are changes in a single nucleotide in...
Mutations
Multiple Allele Traits