While it is indicated that people with FXII deficiency are generally asymptomatic, studies in women with recurrent miscarriages suggest an association with FXII deficiency.

The condition is of importance in the differential diagnosis to other bleeding disorders, specifically the hemophilias: hemophilia A with a deficiency in factor VIII or antihemophilic globulin, hemophilia B with a deficiency in factor IX (Christmas disease), and hemophilia C with a deficiency in factor XI. Other rare forms of bleeding disorders are also in the differential diagnosis.

There is concern that individuals with FXII deficiency are more prone to thrombophilic disease, however, this is at variance with a long term study from Switzerland.

Factor XII deficiency (also Hageman factor deficiency) is a deficiency in the production of factor XII (FXII), a plasma glycoprotein and clotting factor that participates in the coagulation cascade and activates factor XI. FXII appears to be not essential for blood clotting, as individuals with this condition are usually asymptomatic and form blood clots in vivo. FXII deficiency tends to be identified during presurgical laboratory screening for bleeding disorders.

The condition can be inherited or acquired.

Type 1 vWD (60-80% of all vWD cases) is a quantitative defect which is heterozygous for the defective gene. It can arise from failure to secrete vWF into the circulation or from vWF being cleared more quickly than normal. Decreased levels of vWF are detected at 20-50% of normal, i.e. 20-50 IU.

Many patients are asymptomatic or may have mild symptoms and not have clearly impaired clotting, which might suggest a bleeding disorder. Often, the discovery of vWD occurs incidentally to other medical procedures requiring a blood work-up. Most cases of type 1 vWD are never diagnosed due to the asymptomatic or mild presentation of type I and most people usually end up leading a normal life free of complications, with many being unaware that they have the disorder.

Trouble may, however, arise in some patients in the form of bleeding following surgery (including dental procedures), noticeable easy bruising, or menorrhagia (heavy menstrual periods). The minority of cases of type 1 may present with severe hemorrhagic symptoms.

Type 2 vWD (15-30% of cases) is a qualitative defect and the bleeding tendency can vary between individuals. Four subtypes exist: 2A, 2B, 2M, and 2N. These subtypes depend on the presence and behavior of the underlying multimers.

Haemophilia A (or hemophilia A) is a genetic deficiency in clotting factor VIII, which causes increased bleeding and usually affects males. In the majority of cases it is inherited as an X-linked recessive trait, though there are cases which arise from spontaneous mutations.

Factor VIII medication may be used to treat and prevent bleeding in people with haemophilia A.

This condition causes severe infections. it is characterized by elevated immunoglobulins that function poorly.

Other symptoms are:

- Bronchiectasis

- Hepatosplenomegaly

- Pyoderma

- Emphysema

- Diarrhea

There are various symptoms that are presented and are typically associated to a specific site that they appear at. Hypoprothrombinemia is characterized by a poor blood clotting function of prothrombin. Some symptoms are presented as severe, while others are mild, meaning that blood clotting is slower than normal. Areas that are usually affected are muscles, joints, and the brain, however, these sites are more uncommon.

The most common symptoms include:

1. Easy bruising

2. Oral mucosal bleeding - Bleeding of the membrane mucus lining inside of the mouth.

3. Soft tissue bleeding.

4. Hemarthrosis - Bleeding in joint spaces.

5. Epistaxis - Acute hemorrhages from areas of the nasal cavity, nostrils, or nasopharynx.

6. Women with this deficiency experience menorrhagia: prolonged, abnormal heavy menstrual bleeding. This is typically a symptom of the disorder when severe blood loss occurs.

Other reported symptoms that are related to the condition:

1. Prolonged periods of bleeding due to surgery, injury, or post birth.

2. Melena - Associated with acute gastrointestinal bleeding, dark black, tarry feces.

3. Hematochezia - Lower gastrointestinal bleeding, passage of fresh, bright red blood through the anus secreted in or with stools. If associated with upper gastrointestinal bleeding, suggestive of a more life-threatening issue.

Type I: Severe hemorrhages are indicators of a more severe prothrombin deficiency that account for muscle hematomas, intracranial bleeding, postoperative bleeding, and umbilical cord hemorrhage, which may also occur depending on the severity, respectively.

Type II: Symptoms are usually more capricious, but can include a variety of the symptoms described previously. Less severe cases of the disorder typically do not involve spontaneous bleeding.

Characteristic symptoms vary with severity. In general symptoms are internal or external bleeding episodes, which are called "bleeds". People with more severe haemophilia suffer more severe and more frequent bleeds, while people with mild haemophilia usually suffer more minor symptoms except after surgery or serious trauma. In cases of moderate haemophilia symptoms are variable which manifest along a spectrum between severe and mild forms.

In both haemophilia A and B, there is spontaneous bleeding but a normal bleeding time, normal prothrombin time, normal thrombin time, but prolonged partial thromboplastin time. Internal bleeding is common in people with severe haemophilia and some individuals with moderate haemophilia. The most characteristic type of internal bleed is a joint bleed where blood enters into the joint spaces. This is most common with severe haemophiliacs and can occur spontaneously (without evident trauma). If not treated promptly, joint bleeds can lead to permanent joint damage and disfigurement. Bleeding into soft tissues such as muscles and subcutaneous tissues is less severe but can lead to damage and requires treatment.

Children with mild to moderate haemophilia may not have any signs or symptoms at birth especially if they do not undergo circumcision. Their first symptoms are often frequent and large bruises and haematomas from frequent bumps and falls as they learn to walk. Swelling and bruising from bleeding in the joints, soft tissue, and muscles may also occur. Children with mild haemophilia may not have noticeable symptoms for many years. Often, the first sign in very mild haemophiliacs is heavy bleeding from a dental procedure, an accident, or surgery. Females who are carriers usually have enough clotting factors from their one normal gene to prevent serious bleeding problems, though some may present as mild haemophiliacs.

In terms of the symptoms of Hemophilia A there are internal or external bleeding episodes. Individuals with more severe haemophilia suffer more severe and more frequent bleeding, while others with mild haemophilia typically suffer more minor symptoms except after surgery or serious trauma. Moderate haemophiliacs have variable symptoms which manifest along a spectrum between severe and mild forms.

Prolonged bleeding from a venepuncture or heelprick is another common early sign of haemophilia, these signs may lead to blood tests which indicates haemophilia. In other people, especially those with moderate or mild haemophilia any trauma will lead to the first serious "bleed". Haemophilia leads to a severely increased risk of prolonged bleeding from common injuries, or in severe cases bleeding may be spontaneous and without obvious cause. Bleeding may occur anywhere in the body, superficial bleeding such as those caused by abrasions, or shallow lacerations may be prolonged and the scab may easily be broken up due to the lack of fibrin, which may cause re-bleeding. While superficial bleeding is troublesome, some of the more serious sites of bleeding are:

- Joints

- Muscles

- Digestive tract

- Brain

Muscle and joint haemorrhages - or haemarthrosis - are indicative of haemophilia, while digestive tract and cerebral haemorrhages are also germane to other coagulation disorders.Though typically not life-threatening, joint bleeding is one of the most serious symptoms of haemophilia. Repeated bleeds into a joint capsule can cause permanent joint damage and disfigurement resulting in chronic arthritis and disability. Joint damage is not a result of blood in the capsule but rather the healing process. When blood in the joint is broken down by enzymes in the body, the bone in that area is also degraded, this exerts a lot of pain upon the person afflicted with the disease.

ZAP70 deficiency, or zeta-chain-associated protein 70 kD deficiency, is a rare autosomal recessive form of severe combined immunodeficiency (SCID).

It is associated with ZAP70.

Activated protein C resistance (APCR) is a hemostatic disorder characterized by a poor anticoagulant response to activated protein C (APC). This results in an increased risk of venous thrombosis, which can cause problems with circulation, such as pulmonary embolism.

The disorder can be acquired or inherited, the hereditary form having an autosomal dominant inheritance pattern.

Haemorrhagic disease of the newborn, also known as vitamin K deficiency bleeding (VKDB), is a coagulation disturbance in newborn infants due to vitamin K deficiency. As a consequence of vitamin K deficiency there is an impaired production of coagulation factors II, VII, IX, X, protein C and protein S by the liver, resulting in excessive bleeding (hemorrhage).

Bernard–Soulier syndrome often presents as a bleeding disorder with symptoms of:

Hyaluronidase deficiency (also known as "mucopolysaccharidosis type IX") is a condition caused by mutations in HYAL1, and characterized by multiple soft-tissue masses.

The signs and symptoms in glycogen storage disease type IX include:

- Enlarged liver

- Slowed growth

- Motor development delay (mild)

- Low blood sugar accompanied by ketosis

- Lack of muscle tone

Most of these signs and symptoms diminish as adulthood sets in.

The disease causes an increased risk of bleeding. The most common sites of bleeding are the umbilicus, mucous membranes, gastrointestinal tract, circumcision and venepunctures.

In terms of the signs/symptoms of haemophilia C, unlike individuals with Haemophilia A and B, people affected by it are not ones to bleed spontaneously. In these cases, haemorrhages tend to happen after a major surgery or injury. However, people affected with haemophilia C might experience symptoms closely related to those of other forms of haemophilia such as the following:

The presentation of hemophilia B is consistent with easy bruising, urinary tract bleed and nosebleeds. Additionally, the affected individual may experience bleeding into their joints.

This defect leads to a multi-systemic disorder of the connective tissue, muscles, central nervous system (CNS), and cardiovascular system. Homocystinuria represents a group of hereditary metabolic disorders characterized by an accumulation of the amino acid homocysteine in the serum and an increased excretion of homocysteine in the urine. Infants appear to be normal and early symptoms, if any are present, are vague.

Signs and symptoms of homocystinuria that may be seen include the following:

Nezelof syndrome (also known as Thymic dysplasia with normal immunoglobulins) is an autosomal recessive congenital immunodeficiency condition due to underdevelopment of the thymus. The defect is a type of purine nucleoside phosphorylase deficiency with inactive phosphorylase, this results in an accumulation of deoxy-GTP which inhibits ribonucleotide reductase. Ribonucleotide reductase catalyzes the formation of deoxyribonucleotides from ribonucleotides, thus, DNA replication is inhibited.

Protein S deficiency is a disorder associated with increased risk of venous thrombosis. Protein S, a vitamin K-dependent physiological anticoagulant, acts as a nonenzymatic cofactor to activate protein C in the degradation of factor Va and factor VIIIa. Decreased (antigen) levels or impaired function of protein S leads to decreased degradation of factor Va and factor VIIIa and an increased propensity to venous thrombosis. Protein S circulates in human plasma in two forms: approximately 60 percent is bound to complement component C4b β-chain while the remaining 40 percent is free, only free protein S has activated protein C cofactor activity

An estimated 64 percent of patients with venous thromboembolism may have activated protein C resistance.

Severe complications are much more common in cases of severe and moderate haemophilia. Complications may arise from the disease itself or from its treatment:

- Deep internal bleeding, e.g. deep-muscle bleeding, leading to swelling, numbness or pain of a limb.

- Joint damage from haemarthrosis (haemophilic arthropathy), potentially with severe pain, disfigurement, and even destruction of the joint and development of debilitating arthritis.

- Transfusion transmitted infection from blood transfusions that are given as treatment.

- Adverse reactions to clotting factor treatment, including the development of an immune inhibitor which renders factor replacement less effective.

- Intracranial haemorrhage is a serious medical emergency caused by the buildup of pressure inside the skull. It can cause disorientation, nausea, loss of consciousness, brain damage, and death.

Haemophilic arthropathy is characterized by chronic proliferative synovitis and cartilage destruction. If an intra-articular bleed is not drained early, it may cause apoptosis of chondrocytes and affect the synthesis of proteoglycans. The hypertrophied and fragile synovial lining while attempting to eliminate excessive blood may be more likely to easily rebleed, leading to a vicious cycle of hemarthrosis-synovitis-hemarthrosis. In addition, iron deposition in the synovium may induce an inflammatory response activating the immune system and stimulating angiogenesis, resulting in cartilage and bone destruction.

No cure currently exists; however, gene therapy has been proposed.

Haemophilia C is caused by a deficiency of coagulation factor XI and is distinguished from haemophilia A and B by the fact it does not lead to bleeding into the joints. Furthermore, it has autosomal recessive inheritance, since the gene for factor XI is located on chromosome 4 (near the prekallikrein gene); and it is not completely recessive, individuals who are heterozygous also show increased bleeding.

Many mutations exist, and the bleeding risk is not always influenced by the severity of the deficiency. Hemophilia C is developed on occasion in individuals with systemic lupus erythematosus, because of inhibitors to the FXI protein.