Osteogenesis Imperfecta (OI): A genetic disorder characterized by fragile bones, often leading to recurrent fractures, and can also present with joint hyperlaxity due to the collagen defect affecting not just bone but also connective tissue.

Ehlers-Danlos Syndrome (EDS): A group of disorders that affect connective tissues supporting the skin, bones, blood vessels, and many other organs and tissues. Joint hyperlaxity is a hallmark, and while fractures are not as common as in OI, they can occur, especially in the hypermobile type of EDS.
Rheumatoid Arthritis (RA): Although more commonly associated with joint inflammation and destruction, some patients with RA can experience joint laxity and are at increased risk of osteoporotic fractures due to chronic inflammation and steroid treatment.
Osteoporosis: Primarily known for causing an increased risk of fractures, osteoporosis can sometimes be associated with hyperlaxity, particularly in the context of secondary osteoporosis due to conditions like hyperthyroidism or Cushing's syndrome, which can also affect connective tissue.

Cushing's Syndrome: A condition caused by having too much of the hormone cortisol in the body. It can lead to osteoporosis and fractures, and while not primarily associated with joint hyperlaxity, the hormonal imbalance can affect connective tissue, making it a critical diagnosis not to miss due to its potential for severe complications.
Multiple Myeloma: A cancer of plasma cells that can lead to bone weakening and fractures. Joint hyperlaxity is not a primary feature, but the disease's impact on bone health and potential for causing hypercalcemia (which can indirectly affect muscle and joint function) makes it a diagnosis that should not be overlooked.

Marfan Syndrome: A disorder that affects the connective tissue in many parts of the body. While it's known for affecting the heart, eyes, blood vessels, and skeleton, joint hyperlaxity is common, and although fractures are not the most prominent feature, the skeletal system can be affected, leading to an increased risk of fractures in some cases.
Stickler Syndrome: A genetic disorder characterized by distinctive facial features, eye abnormalities, hearing loss, and joint problems. It can also include skeletal abnormalities that might increase the risk of fractures, and joint hyperlaxity is a common feature.
Larsen Syndrome: A rare genetic disorder that affects the development of bones and joints, leading to joint dislocations and hyperlaxity. Fractures can occur due to the abnormal bone and joint structure.