Early-onset osteoporosis: Rare monogenic forms elucidate the complexity of disease pathogenesis beyond type I collagen

Early-onset osteoporosis (EOOP), characterized by low BMD and fractures, affects children, men aged <50 years or pre-menopausal women. EOOP may be secondary to e.g., a chronic illness, long-term medication, or nutritional deficiencies. If no such cause is identified, EOOP is regarded primary and may then be related to rare variants in genes playing a pivotal role in bone homeostasis. If the cause remains unknown, EOOP is considered idiopathic. The scope of this review is to guide through...