This topic is a new entry in the area of cellular calcium signaling: yet, it now spans the entire area, with discoveries that cover both genetic and acquired pathologies, even offering glimpses in the direction of therapy. Cellular calcium homeostasis, and thus calcium signalling, is mainly regulated by membrane intrinsic proteins and calcium sensor proteins. Both classes may be involved in pathological processes that affect both human and animals, ranging from common and important diseases (e.g. migraine, diabetes, epilepsia, manic depression, infertility, various types of cancer, Alzheimer's disease, muscular dystrophy) to rare genetic conditions (e.g., a number of genetic heart conditions, autoimmune retinopathies, night blindness, hereditary amyloid polyneuropathy, malignant hyperthermia, cerebellar ataxia, atherothrombotic disease). Clearly, the topic has now become not only very large, but also very stimulating. Its extensive critical coverage is likely to eventually stimulate fruitful interdisciplinary discussions.