Symptoms can be extremely varied among those suffering from pyruvate kinase deficiency. The majority of those suffering from the disease are detected at birth while some only present symptoms during times of great physiological stress such as pregnancy, or with acute illnesses (viral disorders). Symptoms are limited to or most severe during childhood. Among the symptoms of pyruvate kinase deficiency are:

- Mild to severe hemolytic Anemia

- Cholecystolithiasis

- Tachycardia

- Hemochromatosis

- Icteric sclera

- Splenomegaly

- Leg ulcers

- Jaundice

- Fatigue

- Shortness of breath

Pyruvate kinase deficiency is an inherited metabolic disorder of the enzyme pyruvate kinase which affects the survival of red blood cells. Both autosomal dominant and recessive inheritance have been observed with the disorder; classically, and more commonly, the inheritance is autosomal recessive. Pyruvate kinase deficiency is the second most common cause of enzyme-deficient hemolytic anemia, following G6PD deficiency.

Most individuals with G6PD deficiency are asymptomatic.

Symptomatic patients are almost exclusively male, due to the X-linked pattern of inheritance, but female carriers can be clinically affected due to unfavorable lyonization, where random inactivation of an X-chromosome in certain cells creates a population of G6PD-deficient red blood cells coexisting with unaffected red blood cells. A female with one affected X chromosome will show the deficiency in approximately half of her red blood cells. However, in rare cases, including double X-deficiency, the ratio can be much more than half, making the individual almost as sensitive as males.

Red blood cell breakdown (also known as hemolysis) in G6PD deficiency can manifest in a number of ways, including the following:

- Prolonged neonatal jaundice, possibly leading to kernicterus (arguably the most serious complication of G6PD deficiency)

- Hemolytic crises in response to:

- Illness (especially infections)

- Certain drugs (see below)

- Certain foods, most notably broad beans from which the word favism derives

- Certain chemicals

- Diabetic ketoacidosis

- Very severe crises can cause acute kidney failure

Favism may be formally defined as a hemolytic response to the consumption of fava beans, also known as broad beans. Important to note is that all individuals with favism show G6PD deficiency, but not all individuals with G6PD deficiency show favism. The condition is known to be more prevalent in infants and children, and G6PD genetic variant can influence chemical sensitivity. Other than this, the specifics of the chemical relationship between favism and G6PD are not well understood.

The low incidence of this syndrome is often related to aldolase A's essential glycolytic role along with its exclusive expression in blood and skeletal muscle. Early developmental reliance and constitutive function prevents severe mutation in successful embryos. Infrequent documentation thus prevents clear generalisation of symptoms and causes. However five cases have been well described. ALDOA deficiency is diagnosed through reduced aldoA enzymatic activity, however, both physiological response and fundamental causes vary.

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.

Hexokinase deficiency is an anemia-causing condition associated with inadequate hexokinase. Specifically, the HK1 isozyme is involved.

An acronym for Hexokinase deficiency is HK deficiency, and it is a genetic disease. The person must be homozygous for the trait, as being heterozygous would just make the person a carrier of that mutated gene.

The cause of hexokinase deficiency is linked to mutations of the HK gene and the encoding of the HK enzyme. The result of the mutations lead to reduction in HK activity.

Glucose-6-phosphate dehydrogenase deficiency (G6PDD) is an inborn error of metabolism that predisposes to red blood cell breakdown. Most of the time, those who are affected have no symptoms. Following a specific trigger yellowish skin, dark urine, shortness of breath, and feeling tired. Complications can include anemia and newborn jaundice. Some people never have symptoms.

It is an X-linked recessive disorder that results in defective glucose-6-phosphate dehydrogenase enzyme. Red blood cell breakdown may be triggered by infections, certain medication, stress, or foods such as fava beans. Depending on the specific mutation the severity of the condition may vary. Diagnosis is based on symptoms and supported by blood tests and genetic testing.

Avoiding triggers is important. Treatment of acute episodes may include medications for infection, stopping the offending medication, or blood transfusions. Jaundice in newborns may be treated with special lights. It is recommended that people be tested for G6PDD before certain medications, such as primaquine, are taken.

About 400 million people have the condition globally. It is particularly common in certain parts of Africa, Asia, the Mediterranean, and the Middle East. Males are affected more often than females. In 2015 it is believed to have resulted in 33,000 deaths. Carriers of the G6PDD allele may be partially protected against malaria.

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.

The defining characteristic of this form of the disorder is hemolytic anemia, in which red blood cells break down prematurely. Muscle weakness and pain are not as common in patients with hemolytic PFK deficiency.

Phosphofructokinase deficiency also presents in a rare infantile form. Infants with this deficiency often display floppy infant syndrome (hypotonia), arthrogryposis, encephalopathy and cardiomyopathy. The disorder can also manifest itself in the central nervous system, usually in the form of seizures. PFK deficient infants also often have some type of respiratory issue. Survival rate for the infantile form of PFK deficiency is low, and the cause of death is often due to respiratory failure.

Aldolase A deficiency, also called ALDOA deficiency, red cell aldolase deficiency or glycogen storage disease type 12 (GSD XII) is an autosomal recessive metabolic disorder resulting in a deficiency of the enzyme aldolase A; the enzyme is found predominantly in red blood cells and muscle tissue. The deficiency may lead to hemolytic anaemia as well as myopathy associated with exercise intolerance and rhabdomyolysis in some cases.

Though expressivity is varied depending on the mutation responsible for decrease in enzyme function, severe cutaneous sensitivity is present in most cases of this Porphyria. An estimated 30–40% of cases are due to the C73R mutation, which decreases stability of the enzyme and results in <1% of its activity. Exposure to long-wave ultraviolet light causes the affected skin to thicken and produce vesicles that are prone to rupture and infection; these secondary infections, along with bone resorption, can lead to disfigurement of the sun-exposed face and extremities.

Enzyme dysfunction prevents the normal production of heme and hemolytic anemia is another common symptom, though a lack of hemolysis in this disease is possible. Porphyrins additionally accumulate in the bone and teeth, resulting in erythrodontia.

When unexpected attacks occur, abdominal pain, as well as vomiting and constipation commonly follow the attacks. Exposure to the sunlight can cause discomfort and result in blistering, consciousness of heat, and swelling and redness of the skin.

Purine nucleoside phosphorylase deficiency, often called PNP-deficiency, is a rare autosomal recessive metabolic disorder which results in immunodeficiency.

Enolase Deficiency is a rare genetic disorder of glucose metabolism. Partial deficiencies have been observed in several caucasian families. The deficiency is transmitted through an autosomal dominant inheritance pattern. The gene for Enolase 1 has been localized to Chromosome 1 in humans. Enolase deficiency, like other glycolytic enzyme deficiences, usually manifests in red blood cells as they rely entirely on anaerobic glycolysis. Enolase deficiency is associated with a spherocytic phenotype and can result in hemolytic anemia, which is responsible for the clinical signs of Enolase deficiency.

Most people do not have symptoms. It can cause a mild to moderate enlargement of the spleen, splenomegaly, as well as hemolytic anemia (which is the form of anemia due to abnormal breakdown of red blood cells prematurely). Too much hemoglobin C can reduce the number and size of red blood cells in the body, causing mild anemia. Occasionally, jaundice may occur. Some persons with this disease may develop gallstones that require treatment. Continued hemolysis may produce pigmented gallstones, an unusual type of gallstone composed of the dark-colored contents of red blood cells.

Gunther disease, also known as congenital erythropoietic porphyria (CEP), uroporphyrinogen III synthase deficiency and UROS deficiency, is a congenital form of erythropoietic porphyria. The word porphyria originated from the Greek word porphura. Porphura actually means "purple pigment", which, in suggestion, the color that the body fluid changes when a person has Gunther's disease. It is a rare, autosomal recessive metabolic disorder affecting heme, caused by deficiency of the enzyme uroporphyrinogen cosynthetase. It is extremely rare, with a prevalence estimated at 1 in 1,000,000 or less. There have been times that prior to birth of a fetus, Gunther's disease has been shown to lead to anemia. In milder cases patients have not presented any symptoms until they have reached adulthood. In Gunther's disease, porphyrins are accumulated in the teeth and bones and an increased amount are seen in the plasma, bone marrow, feces, red blood cells, and urine.

Glutathione synthetase deficiency can be classified into three types: mild, moderate and severe.

- "Mild" glutathione synthetase deficiency usually results in the destruction of red blood cells (hemolytic anemia). Rarely, affected people also excrete large amounts of a compound called 5-oxoproline (also called pyroglutamic acid, or pyroglutamate) in their urine (5-oxoprolinuria). This compound builds up when glutathione is not processed correctly in cells.

- Individuals with "moderate" glutathione synthetase deficiency may experience symptoms beginning shortly after birth including hemolytic anemia, 5-oxoprolinuria, and elevated acidity in the blood and tissues (metabolic acidosis).

- In addition to the features present in moderate glutathione synthetase deficiency, individuals affected by the "severe" form of this disorder may experience neurological symptoms. These problems may include seizures; a generalized slowing down of physical reactions, movements, and speech (psychomotor retardation); intellectual disability; and a loss of coordination (ataxia). Some people with severe glutathione synthetase deficiency also develop recurrent bacterial infections.[citation missing]

Hemoglobin c (abbreviated as "Hb C" or "HbC") is an abnormal hemoglobin in which substitution of a glutamic acid residue with a lysine residue at the 6th position of the β-globin chain has occurred (E6K substitution).

The blood film can point towards vitamin deficiency:

- Decreased red blood cell (RBC) count and hemoglobin levels

- Increased mean corpuscular volume (MCV, >100 fL) and mean corpuscular hemoglobin (MCH)

- Normal mean corpuscular hemoglobin concentration (MCHC, 32–36 g/dL)

- The reticulocyte count is decreased due to destruction of fragile and abnormal megaloblastic erythroid precursor.

- The platelet count may be reduced.

- Neutrophil granulocytes may show multisegmented nuclei ("senile neutrophil"). This is thought to be due to decreased production and a compensatory prolonged lifespan for circulating neutrophils, which increase numbers of nuclear segments with age.

- Anisocytosis (increased variation in RBC size) and poikilocytosis (abnormally shaped RBCs).

- Macrocytes (larger than normal RBCs) are present.

- Ovalocytes (oval-shaped RBCs) are present.

- Howell-Jolly bodies (chromosomal remnant) also present.

Blood chemistries will also show:

- An increased lactic acid dehydrogenase (LDH) level. The isozyme is LDH-2 which is typical of the serum and hematopoetic cells.

- Increased homocysteine and methylmalonic acid in Vitamin B deficiency

- Increased homocysteine in folate deficiency

Normal levels of both methylmalonic acid and total homocysteine rule out clinically significant cobalamin deficiency with virtual certainty.

Bone marrow (not normally checked in a patient suspected of megaloblastic anemia) shows megaloblastic hyperplasia.

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.

Glutathione synthetase deficiency is a rare autosomal recessive metabolic disorder that prevents the production of glutathione. Glutathione helps prevent damage to cells by neutralizing harmful molecules generated during energy production. Glutathione also plays a role in processing medications and cancer-causing compounds (carcinogens), and building DNA, proteins, and other important cellular components.

Megaloblastic anemia (or megaloblastic anaemia) is an anemia (of macrocytic classification) that results from inhibition of DNA synthesis during red blood cell production. When DNA synthesis is impaired, the cell cycle cannot progress from the G2 growth stage to the mitosis (M) stage. This leads to continuing cell growth without division, which presents as macrocytosis.

Megaloblastic anemia has a rather slow onset, especially when compared to that of other anemias.

The defect in red cell DNA synthesis is most often due to hypovitaminosis, specifically a deficiency of vitamin B and/or folic acid. Vitamin B deficiency alone will not cause the syndrome in the presence of sufficient folate, as the mechanism is loss of B dependent folate recycling, followed by folate-deficiency loss of nucleic acid synthesis (specifically thymine), leading to defects in DNA synthesis. Folic acid supplementation in the absence of vitamin B prevents this type of anemia (although other vitamin B-specific pathologies may be present). Loss of micronutrients may also be a cause. Copper deficiency resulting from an excess of zinc from unusually high oral consumption of zinc-containing denture-fixation creams has been found to be a cause.

Megaloblastic anemia not due to hypovitaminosis may be caused by antimetabolites that poison DNA production directly, such as some chemotherapeutic or antimicrobial agents (for example azathioprine or trimethoprim).

The pathological state of megaloblastosis is characterized by many large immature and dysfunctional red blood cells (megaloblasts) in the bone marrow and also by hypersegmented neutrophils (those exhibiting five or more nuclear lobes ("segments"), with up to four lobes being normal). These hypersegmented neutrophils can be detected in the peripheral blood (using a diagnostic smear of a blood sample).

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.

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.

Congenital hemolytic anemia (or hereditary hemolytic anemia) refers to hemolytic anemia which is primarily due to congenital disorders.