The incidence of acute TTP in adults is around 1.7–4.5 per million and year. These cases are nearly all due to the autoimmune form of TTP, where autoantibodies inhibit ADAMTS13 activity. The prevalence of USS has not yet been determined but is assumed to constitute less than 5% of all acute TTP cases. The syndrome's inheritance is autosomal recessive, and is more often caused by compound heterozygous than homozygous mutations. The age of onset is variable and can be from neonatal age up to the 5th–6th decade. The risk of relapses differs between affected individuals. Minimization of the burden of disease can be reached by early diagnosis and initiation of prophylaxis if required.

Two Dutch studies have followed hemophilia patients for a number of years. Both studies found that viral infections were common in hemophiliacs due to the frequent blood transfusions which put them at risk of getting blood borne infections such as HIV and hepatitis C. In the latest study which followed patients from 1992 to 2001, the male life expectancy was 59 years. If cases with known viral infections were excluded, the life expectancy was 72, close to that of the general population. 26% of the cases died from AIDS and 22% from hepatitis C.

Several therapy developments for TTP emerged during recent years. Artificially produced ADAMTS13 has been used in mice and testing in humans has been announced. Another drug in development is targeting VWF and its binding sites, thereby reducing VWF-platelet interaction, especially on ULVWF during a TTP episode. Among several (multi-)national data bases a worldwide project has been launched to diagnose USS patients and collect information about them to gain new insights into this rare disease with the goal to optimize patient care.

Two Dutch studies have followed hemophilia patients for a number of years. Both studies found that viral infections were common in hemophiliacs due to the frequent blood transfusions which put them at risk of getting blood borne infections such as HIV and hepatitis C. In the latest study which followed patients from 1992 to 2001, the male life expectancy was 59 years. If cases with known viral infections were excluded, the life expectancy was 72, close to that of the general population. 26% of the cases died from AIDS and 22% from hepatitis C.

The prevalence of vWD is about one in 100 individuals. However, the majority of these people do not have symptoms. The prevalence of clinically significant cases is one per 10,000. Because most forms are rather mild, they are detected more often in women, whose bleeding tendency shows during menstruation. It may be more severe or apparent in people with blood type O.

The vWF gene is located on the short arm "p" of chromosome 12 (12p13.2). It has 52 exons spanning 178kbp. Types 1 and 2 are inherited as autosomal dominant traits and type 3 is inherited as autosomal recessive. Occasionally, type 2 also inherits recessively. vWD occurs in approximately 1% of the population and affects men and women equally.

Haemophilia A occurs in approximately 1 in 5,000 males, while the incidence of haemophilia B is 1 in 30,000 in male population, of these, 85% have haemophilia A and 15% have hemophilia B.

Haemophilia B (or hemophilia B) is a blood clotting disorder caused by a mutation of the factor IX gene, leading to a deficiency of factor IX. It is the second-most common form of haemophilia, rarer than haemophilia A. Haemophilia B was first recognized as a different kind of haemophilia in 1952. It is sometimes called Christmas disease, named after Stephen Christmas, the first patient described with this disease. In addition, the first report of its identification was published in the Christmas edition of the "British Medical Journal".

Anti-platelet autoantibodies in a pregnant woman with ITP will attack the patient's own platelets and will also cross the placenta and react against fetal platelets. Therefore, ITP is a significant cause of fetal and neonatal immune thrombocytopenia. Approximately 10% of newborns affected by ITP will have platelet counts <50,000/uL and 1% to 2% will have a risk of intracerebral hemorrhage comparable to infants with neonatal alloimmune thrombocytopenia (NAIT).

No lab test can reliably predict if neonatal thrombocytopenia will occur. The risk of neonatal thrombocytopenia is increased with:

- Mothers with a history of splenectomy for ITP

- Mothers who had a previous infant affected with ITP

- Gestational (maternal) platelet count less than 100,000/uL

It is recommended that pregnant women with thrombocytopenia or a previous diagnosis of ITP should be tested for serum antiplatelet antibodies. A woman with symptomatic thrombocytopenia and an identifiable antiplatelet antibody should be started on therapy for their ITP which may include steroids or IVIG. Fetal blood analysis to determine the platelet count is not generally performed as ITP-induced thrombocytopenia in the fetus is generally less severe than NAIT. Platelet transfusions may be performed in newborns, depending on the degree of thrombocytopenia. It is recommended that neonates be followed with serial platelet counts for the first few days after birth.,

In an endemic herd, only a minority of the animals develops clinical signs; most animals either eliminate the infection or become asymptomatic carriers. The mortality rate is about 1%, but up to 50% of the animals in the herd can be asymptomatically infected, resulting in losses in production. Once the symptoms appear, paratuberculosis is progressive and affected animals eventually die. The percentage of asymptomatic carriers that develop overt disease is unknown.

In laboratory animals, prevention includes a low-stress environment, an adequate amount of nutritional feed, and appropriate sanitation measurements. Because animals likely ingest bacterial spores from contaminated bedding and feed, regular cleaning is a helpful method of prevention. No prevention methods are currently available for wild animal populations.

Many human diseases can be transmitted to other primates, due to their extensive biological similarities. As a result, centers that hold, treat, or involve close proximity to primates and some other kinds of animals (for example zoos, researchers, and animal hospitals), often take steps to ensure animals are not exposed to human diseases they can catch. In some cases animals are routinely immunized with the same vaccines given to humans.

- Leishmaniasis - Both zoonotic and anthroponotic.

- Influenza, Measles, pneumonia and various other pathogens - Many primates.

- Tuberculosis - Both zoonotic and anthroponotic, with birds, cows, elephants, meerkats, mongooses, monkeys, and pigs known to have been affected.

aHUS can be inherited or acquired, and does not appear to vary by race, gender, or geographic area. As expected with an ultra-rare disease, data on the prevalence of aHUS are extremely limited. A pediatric prevalence of 3.3 cases per million population is documented in one publication of a European hemolytic uremic syndrome (HUS) registry involving 167 pediatric patients.

In terms of treatment/management, bleeding events can be controlled by platelet transfusion.

Most heterozygotes, with few exceptions, do not have a bleeding diathesis. BSS presents as a bleeding disorder due to the inability of platelets to bind and aggregate at sites of vascular endothelial injury. In the event of an individual with mucosal bleeding tranexamic acid can be given.

The affected individual may need to avoid contact sports and medications such as aspirin, which can increase the possibility of bleeding. A potential complication is the possibility of the individual producing antiplatelet antibodies

Hydroxycarbamide and anagrelide are contraindicated during pregnancy and nursing. Essential thrombocytosis can be linked with a three-fold increase in risk of miscarriage. Throughout pregnancy, close monitoring of the mother and fetus is recommended. Low-dose low molecular weight heparin (e.g. enoxaparin) may be used. For life-threatening complications, the platelet count can be reduced rapidly using platelet apheresis, a procedure that removes platelets from the blood and returns the remainder to the patient.

Genetic disorders may also be complex, multifactorial, or polygenic, meaning they are likely associated with the effects of multiple genes in combination with lifestyles and environmental factors. Multifactorial disorders include heart disease and diabetes. Although complex disorders often cluster in families, they do not have a clear-cut pattern of inheritance. This makes it difficult to determine a person’s risk of inheriting or passing on these disorders. Complex disorders are also difficult to study and treat, because the specific factors that cause most of these disorders have not yet been identified. Studies which aim to identify the cause of complex disorders can use several methodological approaches to determine genotype-phenotype associations. One method, the genotype-first approach, starts by identifying genetic variants within patients and then determining the associated clinical manifestations. This is opposed to the more traditional phenotype-first approach, and may identify causal factors that have previously been obscured by clinical heterogeneity, penetrance, and expressivity.

On a pedigree, polygenic diseases do tend to "run in families", but the inheritance does not fit simple patterns as with Mendelian diseases. But this does not mean that the genes cannot eventually be located and studied. There is also a strong environmental component to many of them (e.g., blood pressure).

- asthma

- autoimmune diseases such as multiple sclerosis

- cancers

- ciliopathies

- cleft palate

- diabetes

- heart disease

- hypertension

- inflammatory bowel disease

- intellectual disability

- mood disorder

- obesity

- refractive error

- infertility

Individuals with QPD are at risk for experiencing a number of bleeding symptoms, including joint bleeds, hematuria, and large bruising. In 2010, the genetic cause of QPD has been determined as a mutation involving an extra copy of the uPA (urokinase plasminogen activator) gene http://bloodjournal.hematologylibrary.org/content/115/6/1264.long. The mutation causes overproduction of an enzyme that accelerates blood clot breakdown.

An anthroponotic disease, or anthroponosis, is an infectious disease in which a disease causing agent carried by humans is transferred to other animals. It may cause the same disease or a different disease in other animals. Since humans do not generally inflict bite wounds on other animals, the method of transmissions is always a "soft" contact such as skin to skin transmission. An example is chytridiomycosis which can be spread by humans with the fungus on their skin handling frogs with bare hands.

The reverse situation, a disease transmitted from animals to humans, is known as zoonotic.

It can also be defined as a human-to-human infection with no animal vector.

Purpura fulminans is rare and most commonly occurs in babies and small children but can also be a rare manifestation in adults when it is associated with severe infections. For example, Meningococcal septicaemia is complicated by purpura fulminans in 10–20% of cases among children. Purpura fulminans associated with congenital (inherited) protein C deficiency occurs in 1:500,000–1,000,000 live births.

The disorder is characterized by large amounts of the fibrinolytic enzyme urokinase-type plasminogen activator (u-PA) in platelets. Consequently, stored platelet plasminogen is converted to plasmin, which is thought to play a role in degrading a number of proteins stored in platelet α-granules. These proteins include platelet factor V, Von Willebrand factor, fibrinogen, thrombospondin-1, and osteonectin. There is also a quantitative deficiency in the platelet protein multimerin 1 (MMRN1). Furthermore, upon QPD platelet activation, u-PA can be released into forming clots and accelerate clot lysis, resulting in delayed-onset bleeding (12-24hrs after injury).

The incidence of ET is 0.6-2.5/100,000 per year, the median age at onset is 65–70 years and it is more frequent in females than in males. The incidence in children is 0.09/100,000 per year.

Contact with farm animals can lead to disease in farmers or others that come into contact with infected animals. Glanders primarily affects those who work closely with horses and donkeys. Close contact with cattle can lead to cutaneous anthrax infection, whereas inhalation anthrax infection is more common for workers in slaughterhouses, tanneries and wool mills. Close contact with sheep who have recently given birth can lead to clamydiosis, or enzootic abortion, in pregnant women, as well as an increased risk of Q fever, toxoplasmosis, and listeriosis in pregnant or the otherwise immunocompromised. Echinococcosis is caused by a tapeworm which can be spread from infected sheep by food or water contaminated with feces or wool. Bird flu is common in chickens. While rare in humans, the main public health worry is that a strain of bird flu will recombine with a human flu virus and cause a pandemic like the 1918 Spanish flu. In 2017, free range chickens in the UK were temporarily ordered to remain inside due to the threat of bird flu. Cattle are an important reservoir of cryptosporidiosis and mainly affects the immunocompromised.

Outbreaks of zoonoses have been traced to human interaction with and exposure to animals at fairs, petting zoos, and other settings. In 2005, the Centers for Disease Control and Prevention (CDC) issued an updated list of recommendations for preventing zoonosis transmission in public settings. The recommendations, developed in conjunction with the National Association of State Public Health Veterinarians, include educational responsibilities of venue operators, limiting public and animal contact, and animal care and management.

Bernard–Soulier syndrome (BSS), also called hemorrhagiparous thrombocytic dystrophy, is a rare autosomal recessive coagulopathy (bleeding disorder) that causes a deficiency of "glycoprotein Ib" (GpIb), the receptor for von Willebrand factor. The incidence of BSS is estimated to be less than 1 case per million persons, based on cases reported from Europe, North America, and Japan. BSS is a giant platelet disorder, meaning that it is characterized by abnormally large platelets.

Tyzzer’s disease is an acute epizootic bacterial disease found in rodents, rabbits, dogs, cats, birds, pandas, deer, foals, cattle, and other mammals including gerbils. It is caused by the spore-forming bacterium "Clostridium piliforme", formerly known as "Bacillus piliformis". It is an infectious disease characterized by necrotic lesions on the liver, is usually fatal, and is present worldwide. Animals with the disease become infected through oral ingestion of the bacterial spores and usually die within a matter of days. Animals most commonly affected include young, stressed animals in laboratory environments, such as immature rodents and rabbits. Most commonly affected wild animals include muskrats "(Ondatra zibethicus)" and occasionally cottontail rabbits "(Lepus sylvaticus)". Even today, much remains unknown about Tyzzer’s disease, including how and why it occurs.