Bardet–Biedl syndrome (BBS) is a ciliopathic human genetic disorder that produces many effects and affects many body systems. It is characterized by rod/cone dystrophy, polydactyly, central obesity, hypogonadism, and kidney dysfunction in some cases. Historically, slower mental processing has also been considered a principal symptom but is now not regarded as such. Signs and symptoms
Bardet–Biedl syndrome is a pleiotropic disorder with variable expressivity and a wide range of clinical variability observed both within and between families. The most common clinical features are rod–cone dystrophy, with childhood-onset night-blindness followed by increasing visual loss; postaxial polydactyly; truncal obesity that manifests during infancy and remains problematic throughout adulthood; varying degrees of learning disabilities; male hypogenitalism and complex female genitourinary malformations; and renal dysfunction, a major cause of morbidity and mortality.There is a wide range of secondary features that are sometimes associated with BBS: 147–148  including: 153–154 
Strabismus, cataracts, astigmatism, pigmentary retinopathy, poor visual acuity, low vision, and/or blindness caused by an impaired photoreceptor transport mechanism in the retina. "Brachydactyly, syndactyly of both the hands and feet is common, as is partial syndactyl (most usually between the second and third toes)"
Polyuria/polydipsia (nephrogenic diabetes insipidus)
Ataxia/poor coordination/imbalance
Mild hypertonia (especially lower limbs)
Diabetes mellitus
Hepatic involvement
Anosmia
Auditory deficiencies
Hirschsprung disease and subsequent bowel obstruction has been described. Hypertrophy of interventricular septum and left ventricle and dilated cardiomyopathy.
Transplanting hepatocytes was ineffective, but liver endothelial cells were effective.In the blood, it mainly circulates in a stable 
noncovalent complex with von Willebrand factor. Upon activation by thrombin (factor IIa), it dissociates from the complex to interact with factor IXa in the coagulation cascade. It is a cofactor to factor IXa in the activation of factor X, which, in turn, with its cofactor factor Va, activates more thrombin. Thrombin cleaves fibrinogen into fibrin which polymerizes and crosslinks (using factor XIII) into a blood clot. The factor VIII protein has a half-life of 12 hours in the blood stream when stabilized by the von Willebrand factor. No longer protected by vWF, activated FVIII is proteolytically inactivated in the process (most prominently by activated protein C and factor IXa) and quickly cleared from the blood stream. Factor VIII is not affected by liver disease. In fact, levels usually are elevated in such instances. Medical use
FVIII concentrated from donated blood plasma, or alternatively recombinant FVIIa can be given to hemophiliacs to restore hemostasis. Antibody formation to factor VIII can also be a major concern for patients receiving therapy against bleeding; the incidence of these inhibitors is dependent of various factors, including the factor VIII product itself. Immunostain target
Factor VIII related antigen is used as a target for immunohistochemistry, where endothelial cells, megakaryocytes, platelets and mast cells normally stain positive. Contamination scandal
In the 1980s, some pharmaceutical companies such as Baxter International and Bayer sparked controversy by continuing to sell contaminated factor VIII after new heat-treated versions were available.