Huntington's disease (HD) is one of many neurodegenerative diseases with reported alterations in brain iron homeostasis that may contribute to neuropathogenesis. Iron accumulation in the specific brain areas of neurodegeneration in HD has been proposed based on observations in post-mortem tissue and magnetic resonance imaging studies. Altered magnetic resonance imaging signal within specific brain regions undergoing neurodegeneration has been consistently reported and interpreted as altered levels of brain iron. Biochemical studies using various techniques to measure iron species in human samples, mouse tissue, or in vitro has generated equivocal data to support such an association. Whether elevated brain iron occurs in HD, plays a significant contributing role in HD pathogenesis, or is a secondary effect remains currently unclear.

The recurrent p.Gly41Arg FXYD2 mutation in two new families with IDH confirms that FXYD2 mutation causes hypomagnesaemia. Until now, no other FXYD2 mutations have been reported which could indicate that other FXYD2 mutations will not cause hypomagnesaemia or are embryonically lethal.

In dogs with intervertebral disc disease, vacuum phenomenon is a frequent but inconsistent finding. Although helpful to identify degenerated discs, it is not suitable to identify currently herniated disc with sufficient accuracy.

Parkinson’s disease patients suffer from both motor and nonmotor impairments. There is currently no cure for Parkinson’s disease, and the most commonly used treatment, levodopa, only functions as a temporary relief of motor symptoms. Inhibition of the expression of the L‐tryptophan‐catabolizing enzyme tryptophan 2,3‐dioxygenase (TDO) has been shown to inhibit aging‐related α‐synuclein toxicity in Caenorhabditis elegans. To evaluate TDO inhibition as a potential therapeutic strategy for Parkinson’s disease, a brain‐penetrable, small molecule TDO inhibitor was developed, referred to as NTRC 3531‐0. This compound potently inhibits human and mouse TDO in biochemical and cell‐based assays and is selective over IDO1, an evolutionary unrelated enzyme that catalyzes the same reaction. In mice, NTRC 3531‐0 increased plasma and brain L‐tryptophan levels after oral administration, demonstrating inhibition of TDO activity in vivo. The effect on Parkinson’s disease symptoms was evaluated in a rotenone‐induced Parkinson’s disease mouse model. A structurally dissimilar TDO inhibitor, LM10, was evaluated in parallel. Both inhibitors had beneficial effects on rotenone‐induced motor and cognitive dysfunction as well as rotenone‐induced dopaminergic cell loss and neuroinflammation in the substantia nigra. Moreover, both inhibitors improved intestinal transit and enhanced colon length, which indicates a reduction of the rotenone‐induced intestinal dysfunction. Consistent with this, mice treated with TDO inhibitor showed decreased expression of rotenone‐induced glial fibrillary acidic protein, which is a marker of enteric glial cells, and decreased α‐synuclein accumulation in the enteric plexus. Our data support TDO inhibition as a potential therapeutic strategy to decrease motor, cognitive, and gastrointestinal symptoms in Parkinson’s disease.