Boomerang dysplasia is a lethal form of osteochondrodysplasia known for a characteristic congenital feature in which bones of the arms and legs are malformed into the shape of a boomerang. Death usually occurs in early infancy due to complications arising from overwhelming systemic bone malformations.Osteochondrodysplasias are skeletal disorders that cause malformations of both bone and cartilage. Presentation
Prenatal and neonatal diagnosis of boomerang dysplasia includes several prominent features found in other osteochondrodysplasias, though the "boomerang" malformation seen in the long bones is the delineating factor.Featured symptoms of boomerang dysplasia include: dwarfism (a lethal type of infantile dwarfism caused by systemic bone deformities), underossification (lack of bone formation) in the limbs, spine and ilium (pelvis); proliferation of multinucleated giant-cell chondrocytes (cells that produce cartilage and play a role in skeletal development - chondrocytes of this type are rarely found in osteochondrodysplasias), brachydactyly (shortened fingers) and micromelia (undersized, shortened bones).The characteristic "boomerang" malformation presents intermittently among random absences of long bones throughout the skeleton, in affected individuals. For example, one individual may have an absent radius and fibula, with the "boomerang" formation found in both ulnas and tibias. Another patient may present "boomerang" femora, and an absent tibia. Cause
Mutations in the Filamin B (FLNB) gene cause boomerang dysplasia. FLNB is a cytoplasmic protein that regulates intracellular communication and signalling by cross-linking the protein actin to allow direct communication between the cell membrane and cytoskeletal network, to control and guide proper skeletal development.
Alosetron, sold under the brand name Lotronex among others, is a 5-HT3 antagonist used for the management of severe diarrhea-predominant irritable bowel syndrome (IBS) in women only. It was patented in 1987 and approved for medical use in 2002. It is currently marketed by Prometheus Laboratories Inc. (San Diego). Alosetron was withdrawn from the market in 2000 owing to the occurrence of serious life-threatening gastrointestinal adverse effects, but was reintroduced in 2002 with availability and use restricted. Medical uses
Alosetron is indicated only for women with severe diarrhea-predominant irritable bowel syndrome (IBS-D) who have: 

chronic IBS symptoms (generally lasting 6 months or longer),
had anatomic or biochemical abnormalities of the gastrointestinal tract excluded, and
not responded adequately to conventional therapy.Severe IBS-D includes: diarrhea and 1 or more of the following:

frequent and severe abdominal pain/discomfort,
frequent bowel urgency or fecal incontinence,
disability or restriction of daily activities due to IBS. Efficacy
The phase III trial for approval was published in 2000 as an industry-funded randomised, placebo-controlled trial (PCT). Its authors found 1 mg alosetron, taken orally twice daily for 12 weeks, was associated with a 12% (CI 4.7-19.2) improvement in relief from abdominal pain and discomfort associated with diarrhoea-predominant patients. The prescription of alosetron is currently approved in the U.S. at 0.5 and 1 mg.The FDA Medical Officers Review, dated November 4, 1999, noted: "Patients considered by investigators to fit the diarrhea-predominant subtype had at baseline... stool consistency values that were neither loose nor watery".