Trimethylaminuria is an uncommon metabolic disorder first described in 1970 that affects the body’s ability to produce the enzyme flavin, which monooxygenase 3 (FMO3). This causes trimethylamine to build up and release in excess through a person’s sweat, urine and breath. Trimethylamine gives off a strong, fishy body odor, which is why the disease is more colloquially referred to as, “fish malodor syndrome.” While the disorder is incurable, those afflicted can reduce the fishy smell by avoiding foods like beans, red meats and, understandably, fish.

Trimethylaminuria is the cause of our protagonist’s condition and the starting point for writer/director Analeine Cal y Mayor’s debut film. Although the titular boy, Mica (two child actors, then Douglas Smith), doesn’t learn the specifics of his illness until young adulthood, his life is altered from birth as the doctor in his delivery room takes a quick, unpleasant sniff of his...