Q and A: about health and research

Hartnup disease is a rare inherited metabolic disorder characterized by impaired absorption and renal reabsorption of neutral amino acids, particularly tryptophan. Because tryptophan is an essential precursor for niacin (vitamin B3), affected individuals may develop a secondary niacin deficiency that produces a characteristic photosensitive skin disorder resembling pellagra. The condition provides a fascinating example of how a genetic defect in amino acid transport can lead to nutritional deficiency, neurological dysfunction, and distinctive dermatological manifestations. Introduction Hartnup disease is inherited in an autosomal recessive pattern and results from mutations in the SLC6A19 gene. This gene encodes the neutral amino acid transporter B⁰AT1, which is primarily expressed in the epithelial cells of the small intestine and renal tubules. When this transporter is defective, the body cannot efficiently absorb neutral amino acids from food or reclaim them from urine. Consequen...

Despite decades of effort, ME/CFS (Myalgic Encephalomyelitis/Chronic Fatigue Syndrome) and Long COVID remain poorly understood. One possible reason may be the continued underrepresentation of neurochemical research in these fields. In biomedical science, certainty comes only when cause and effect are demonstrated through rigorous laboratory and imaging tools—yet much of the research on these conditions still skirts around the complex interplay of brain function, hormonal regulation, and psychological symptoms. The Neurobiology of Depression: A Parallel Worth Revisiting There’s a familiar pattern in research on chronic, poorly-defined illnesses: a search for answers that tends to overlook what's been apparent for years—the central role of the brain in both physiological and psychological dysfunction. Beyond well-documented cases of direct brain infections from pathogens, the underlying mechanisms of hormonal and neurochemical imbalance—particularly involving the hypothalamic-pitu...