Symptoms may differ greatly, as apparently modifiers control to some degree the amount of FX that is produced. Some affected individuals have few or no symptoms while others may experience life-threatening bleeding. Typically this bleeding disorder manifests itself as a tendency to easy bruising, nose bleeding, heavy and prolonged menstruation and bleeding during pregnancy and childbirth, and excessive bleeding after dental or surgical interventions. Newborns may bleed in the head, from the umbilicus, or excessively after circumcision. Other bleeding can be encountered in muscles or joints, brain, gut, or urine

While in congenital disease symptoms may be present at birth or show up later, in patients with acquired FX deficiency symptoms typically show up in later life.

In addition to the symptoms associated with immunodeficiency, such as depletion of T-cells, decline of lymphocyte activity, and an abrupt proliferation of both benign and opportunistic infections — PNP-deficiency is often characterized by the development of autoimmune disorders. lupus erythematosus, autoimmune hemolytic anemia, and idiopathic thrombocytopenic purpura have been reported with PNP-deficiency.

Neurological symptoms, such as developmental decline, hypotonia, and mental retardation have also been reported.

Factor X deficiency (X as Roman numeral ten) is a bleeding disorder characterized by a lack in the production of factor X (FX), an enzyme protein that causes blood to clot in the coagulation cascade. Produced in the liver FX when activated cleaves prothrombin to generate thrombin in the intrinsic pathway of coagulation. This process is vitamin K dependent and enhanced by activated factor V.

The condition may be inherited or, more commonly, acquired.

85–90% of IgA-deficient individuals are asymptomatic, although the reason for lack of symptoms is relatively unknown and continues to be a topic of interest and controversy. Some patients with IgA deficiency have a tendency to develop recurrent sinopulmonary infections, gastrointestinal infections and disorders, allergies, autoimmune conditions, and malignancies. These infections are generally mild and would not usually lead to an in-depth workup except when unusually frequent.

They may present with severe reactions including anaphylaxis to blood transfusions or intravenous immunoglobulin due to the presence of IgA in these blood products. Patients have an increased susceptibility to pneumonia and recurrent episodes of other respiratory infections and a higher risk of developing autoimmune diseases in middle age.

IgA deficiency and common variable immunodeficiency (CVID) feature similar B cell differentiation arrests, it does not present the same lymphocyte subpopulation abnormalities. IgA-deficient patients may progress to panhypogammaglobulinemia characteristic of CVID. Selective IgA and CVID are found in the same family.

The following symptoms (signs) are consistent with complement deficiency in general:

The precise symptoms of a primary immunodeficiency depend on the type of defect. Generally, the symptoms and signs that lead to the diagnosis of an immunodeficiency include recurrent or persistent infections or developmental delay as a result of infection. Particular organ problems (e.g. diseases involving the skin, heart, facial development and skeletal system) may be present in certain conditions. Others predispose to autoimmune disease, where the immune system attacks the body's own tissues, or tumours (sometimes specific forms of cancer, such as lymphoma). The nature of the infections, as well as the additional features, may provide clues as to the exact nature of the immune defect.

A variety of neurological symptoms have been associated with carnosinemia. They include: hypotonia, developmental delay, mental retardation, degeneration of axons, sensory neuropathy, tremors, demyelinization, gray matter anomalies, myoclonic seizures, and loss of purkinje fibers.

Tetrahydrobiopterin deficiency (THBD, BHD), also called THB or BH deficiency, is a rare metabolic disorder that increases the blood levels of phenylalanine. Phenylalanine is an amino acid obtained through the diet. It is found in all proteins and in some artificial sweeteners. If tetrahydrobiopterin deficiency is not treated, excess phenylalanine can build up to harmful levels in the body, causing intellectual disability and other serious health problems.

High levels of phenylalanine are present from infancy in people with untreated tetrahydrobiopterin (THB, BH) deficiency. The resulting signs and symptoms range from mild to severe. Mild complications may include temporary low muscle tone. Severe complications include intellectual disability, movement disorders, difficulty swallowing, seizures, behavioral problems, progressive problems with development, and an inability to control body temperature.

It was first characterized in 1975.

Vaccinations for encapsulated organisms (e.g., "Neisseria meningitidis" and "Streptococcus pneumoniae") is crucial for preventing infections in complement deficiencies. Among the possible complications are the following:

- Deficiencies of the terminal complement components increases susceptibility to infections by Neisseria.

LRBA deficiency presents as a syndrome of autoimmunity, lymphoproliferation, and humoral immune deficiency. Predominant clinical problems include idiopathic thrombocytopenic purpura (ITP), autoimmune hemolytic anemia (AIHA), and an autoimmune enteropathy. Before the discovery of these gene mutations, patients were diagnosed with common variable immune deficiency (CVID), which is characterized by low antibody levels and recurrent infections. Infections mostly affect the respiratory tract, as many patients suffer from chronic lung disease, pneumonias, and bronchiectasis. Lymphocytic interstitial lung disease (ILD) is also observed, which complicates breathing and leads to impairment of lung function and mortality. Infections can also occur at other sites, such as the eyes, skin and gastrointestinal tract. Many patients suffer from chronic diarrhea and inflammatory bowel disease. Other clinical features can include hepatosplenomegaly, reoccurring warts, growth retardation, allergic dermatitis, and arthritis. Notably, LRBA deficiency has also been associated with type 1 diabetes mellitus. There is significant clinical phenotypic overlap with disease caused by CTLA4 haploinsufficiency. Since LRBA loss results in a loss of CTLA4 protein, the immune dysregulation syndrome of LRBA deficient patients can be attributed to the secondary loss of CTLA4. Because the predominant features of the disease include autoantibody-mediated disease (AIHA, ITP), Treg defects (resembling those found in CTLA4 haploinsufficient patients), autoimmune infiltration (of non-lymphoid organs, also resembling that found in CTLA4 haploinsufficient patients), and enteropathy, the disease has been termed LATAIE for LRBA deficiency with autoantibodies, Treg defects, autoimmune infiltration, and enteropathy.

Selective immunoglobulin A (IgA) deficiency (SIgAD) is a genetic immunodeficiency, a type of hypogammaglobulinemia. People with this deficiency lack immunoglobulin A (IgA), a type of antibody that protects against infections of the mucous membranes lining the mouth, airways, and digestive tract. It is defined as an undetectable serum IgA level in the presence of normal serum levels of IgG and IgM, in persons older than 4 years. It is the most common of the primary antibody deficiencies. Most such persons remain healthy throughout their lives and are never diagnosed.

This disorder causes neurological problems, including mental retardation, brain atrophy and ventricular dilation, myoclonus, hypotonia, and epilepsy.

It is also associated with growth retardation, megaloblastic anemia, pectus excavatum, scoliosis, vomiting, diarrhea, and hepatosplenomegaly.

Signs of vitamin E deficiency include the following:

- Neuromuscular problems-such as spinocerebellar ataxia and myopathies.

- Neurological problems-may include dysarthria, absence of deep tendon reflexes, loss of the ability to sense vibration and detect where body parts are in three dimensional space, and positive Babinski sign.

- Hemolytic anemia-due to oxidative damage to red blood cells

- Retinopathy

- Impairment of the immune response

There is also some laboratory evidence that vitamin E deficiency can cause male infertility.

The signs and symptoms of DOCK8 deficiency are similar to the autosomal dominant form, STAT3 deficiency. However, in DOCK8 deficiency, there is no skeletal or connective tissue involvement, and affected individuals do not have the characteristic facial features of those with autosomal dominant hyper-IgE syndrome. DOCK8 deficient children often have eczema, respiratory and skin staphylococcus infections.

Beyond these, many other recurrent infections have been observed, including recurrent fungal infections and recurrent viral infections (including molluscum contagiosum, herpes simplex, and herpes zoster), recurrent upper respiratory infection (including "Streptococcus pneumoniae", "Haemophilus influenzae", respiratory syncytial virus, and adenovirus), recurrent sinusitis, recurrent otitis media, mastoiditis, pneumonia, bronchitis with bronchiectasis, osteomyelitis, candidiasis, meningitis (caused by cryptococcus or H. influenzae), pericarditis, salmonella enteritis, and giardiasis. Other dermatologic problems include squamous-cell carcinoma/dysplasia (vulvar, anal, and facial). Immune problems are also common, including autoimmune hemolytic anemia, severe allergies (both food and environmental), asthma, and reactive airway disease. The nervous system may also be affected; observed conditions in DOCK8 deficient people include hemiplegia, ischemic stroke, subarachnoid hemorrhage, and facial paralysis. Vascular complications are common, including aortic aneurysm, cerebral aneurysm, vessel occlusion and underperfusion, and leukocytoclastic vasculitis.

Copper deficiency can cause a wide variety of neurological problems including, myelopathy, peripheral neuropathy, and optic neuropathy.

Primary immunodeficiencies are disorders in which part of the body's immune system is missing or does not function normally. To be considered a "primary" immunodeficiency, the cause of the immune deficiency must not be secondary in nature (i.e., caused by other disease, drug treatment, or environmental exposure to toxins). Most primary immunodeficiencies are genetic disorders; the majority are diagnosed in children under the age of one, although milder forms may not be recognized until adulthood. While there are over 100 recognized PIDs, most are very rare. About 1 in 500 people in the United States are born with a primary immunodeficiency. Immune deficiencies can result in persistent or recurring infections, autoinflammatory disorders, tumors, and disorders of various organs. There are currently no cures for these conditions; treatment is palliative and consists of managing infections and boosting the immune system.

Fumarase deficiency causes encephalopathy, severe mental retardation, unusual facial features, brain malformation, and epileptic seizures due to an abnormally low amount of fumarase in cells. It can initially present with polyhydramnios on prenatal ultrasound. Affected neonates may demonstrate nonspecific signs of poor feeding and hypotonia. Laboratory findings in neonates may indicate polycythemia, leukopenia, or neutropenia. As they age, neurological deficits begin to manifest with seizures, dystonias, and severe developmental delay.

Vitamin E deficiency or hypovitaminosis E is a deficiency of vitamin E. It causes nerve problems due to poor conduction of electrical impulses along nerves due to changes in nerve membrane structure and function.

Signs and symptoms of a biotinidase deficiency can appear several days after birth. These include seizures, hypotonia and muscle/limb weakness, ataxia, paresis, hearing loss, optic atrophy, skin rashes (including seborrheic dermatitis and psoriasis), and alopecia. If left untreated, the disorder can rapidly lead to coma and death.

Biotinidase deficiency can also appear later in life. This is referred to as "late-onset" biotinidase deficiency. The symptoms are similar, but perhaps more mild, because if an individual survives the neonatal period they likely have some residual activity of biotin-related enzymes. Studies have noted individuals who were asymptomatic until adolescence or early adulthood. One study pointed out that untreated individuals may not show symptoms until age 21. Furthermore, in rare cases, even individuals with profound deficiencies of biotinidase can be asymptomatic.

Symptom severity is predictably correlated with the severity of the enzyme defect. Profound biotinidase deficiency refers to situations where enzyme activity is 10% or less. Individuals with partial biotinidase deficiency may have enzyme activity of 10-30%.

Functionally, there is no significant difference between dietary biotin deficiency and genetic loss of biotin-related enzyme activity. In both cases, supplementation with biotin can often restore normal metabolic function and proper catabolism of leucine and isoleucine.

The symptoms of biotinidase deficiency (and dietary deficiency of biotin) can be quite severe. A 2004 case study from Metametrix detailed the effects of biotin deficiency, including aggression, cognitive delay, and reduced immune function.

Another common symptom of copper deficiency is peripheral neuropathy, which is numbness or tingling that can start in the extremities and can sometimes progress radially inward towards the torso. In an Advances in Clinical Neuroscience & Rehabilitation (ACNR) published case report, a 69-year-old patient had progressively worsened neurological symptoms. These symptoms included diminished upper limb reflexes with abnormal lower limb reflexes, sensation to light touch and pin prick was diminished above the waist, vibration sensation was lost in the sternum, and markedly reduced proprioception or sensation about the self’s orientation. Many people suffering from the neurological effects of copper deficiency complain about very similar or identical symptoms as the patient. This numbness and tingling poses danger for the elderly because it increases their risk of falling and injuring themselves. Peripheral neuropathy can become very disabling leaving some patients dependent on wheel chairs or walking canes for mobility if there is lack of correct diagnosis. Rarely can copper deficiency cause major disabling symptoms. The deficiency will have to be present for an extensive amount of time until such disabling conditions manifest.

Biotinidase deficiency is an autosomal recessive metabolic disorder in which biotin is not released from proteins in the diet during digestion or from normal protein turnover in the cell. This situation results in biotin deficiency.

Biotin, also called vitamin B, is an important water-soluble nutrient that aids in the metabolism of fats, carbohydrates, and proteins. Biotin deficiency can result in behavioral disorders, lack of coordination, learning disabilities and seizures. Biotin supplementation can alleviate and sometimes totally stop such symptoms.

Symptoms of enolase deficiency include exercise-induced myalgia and generalized muscle weakness and fatigability, both with onset in adulthood. Symptoms also include muscle pain without cramps, and decreased ability to sustain long term exercise.

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.

Loss of appetite and weight loss can occur. Additional signs are weakness, sore tongue, headaches, heart palpitations, irritability, and behavioral disorders. In adults, anemia (macrocytic, megaloblastic anemia) can be a sign of advanced folate deficiency.

Women with folate deficiency who become pregnant are more likely to give birth to low birth weight premature infants, and infants with neural tube defects. In infants and children, folate deficiency can lead to failure to thrive or slow growth rate, diarrhea, oral ulcers, megaloblastic anemia, neurological deterioration. Microcephaly, irritability, developmental delay, seizures, blindness and cerebellar ataxia can also be observed.

LRBA deficiency is a rare genetic disorder of the immune system. This disorder is caused by a mutation in the gene "LRBA". LRBA stands for “Lipopolysaccharide (LPS)-responsive vesicle trafficking, beach- and anchor-containing” gene. This condition is characterized by autoimmunity, lymphoproliferation, and immune deficiency. It was first described by Gabriela Lopez-Herrera from University College London in 2012. Investigators in the laboratory of Dr. Michael Lenardo at National Institute of Allergy and Infectious Diseases, the National Institutes of Health and Dr. Michael Jordan at Cincinnati Children’s Hospital Medical Center later described this condition and therapy in 2015.