Huntingtin (HTT) is a large, multidomain protein encoded by the *HTT* gene, primarily expressed in neurons and involved in critical cellular processes such as vesicle transport, synaptic signaling, and transcriptional regulation. Mutations in *HTT*, specifically an abnormal expansion of CAG repeats (>36) in exon 1. result in the production of mutant huntingtin (mHTT) with an elongated polyglutamine (polyQ) tract. This mutation causes Huntington’s disease (HD), a fatal neurodegenerative disorder characterized by motor dysfunction, cognitive decline, and psychiatric symptoms. The pathogenic mHTT tends to aggregate, forming toxic intracellular inclusions that disrupt proteostasis, impair mitochondrial function, and trigger neuronal apoptosis.
Huntingtin antibodies are essential tools for studying HD mechanisms and diagnostics. They target specific epitopes, such as the N-terminal region (common in aggregation studies), the polyQ stretch (to distinguish mutant from wild-type HTT), or phosphorylated residues (to track post-translational modifications). These antibodies enable detection of HTT expression levels, localization, and aggregation via techniques like Western blot, immunofluorescence, or ELISA. Selective antibodies against mHTT are crucial for evaluating therapeutic strategies, including antisense oligonucleotides or gene editing, aimed at reducing toxic protein levels. However, challenges remain in ensuring antibody specificity due to sequence homology between wild-type and mutant HTT, necessitating rigorous validation using knockout controls or patient-derived samples. Commercial HTT antibodies are widely used in research, yet variability between clones and batches underscores the importance of careful experimental design in HD studies.