The disorder affects about 1 out of 1,000,000 people, however epidemiological data are limited and there are regional differences due to cofounder effect (e.g. in Canada) or intermarriage.

Hypoglycemia due to endogenous insulin can be congenital or acquired, apparent in the newborn period, or many years later. The hypoglycemia can be severe and life-threatening or a minor, occasional nuisance. By far the most common type of severe but transient hyperinsulinemic hypoglycemia occurs accidentally in persons with type 1 diabetes who take insulin.

- Hypoglycemia due to endogenous insulin

- Congenital hyperinsulinism

- Transient neonatal hyperinsulinism (mechanism not known)

- Focal hyperinsulinism (K channel disorders)

- Paternal SUR1 mutation with clonal loss of heterozygosity of 11p15

- Paternal Kir6.2 mutation with clonal loss of heterozygosity of 11p15

- Diffuse hyperinsulinism

- K channel disorders

- SUR1 mutations

- Kir6.2 mutations

- Glucokinase gain-of-function mutations

- Hyperammonemic hyperinsulinism (glutamate dehydrogenase gain-of-function mutations)

- Short chain acyl coenzyme A dehydrogenase deficiency

- Carbohydrate-deficient glycoprotein syndrome (Jaeken's Disease)

- Beckwith-Wiedemann syndrome(suspected due to hyperinsulinism but pathophysiology uncertain: 11p15 mutation or IGF2 excess)

- Acquired forms of hyperinsulinism

- Insulinomas (insulin-secreting tumors)

- Islet cell adenoma or adenomatosis

- Islet cell carcinoma

- Adult nesidioblastosis

- Autoimmune insulin syndrome

- Noninsulinoma pancreatogenous hypoglycemia

- Reactive hypoglycemia (also see idiopathic postprandial syndrome)

- Gastric dumping syndrome

- Drug induced hyperinsulinism

- Sulfonylurea

- Aspirin

- Pentamidine

- Quinine

- Disopyramide

- Bordetella pertussis vaccine or infection

- D-chiro-inositol and myo-inositol

- Hypoglycemia due to exogenous (injected) insulin

- Insulin self-injected for treatment of diabetes (i.e., diabetic hypoglycemia)

- Insulin self-injected surreptitiously (e.g., Munchausen syndrome)

- Insulin self-injected in a suicide attempt or successful suicide

- Various forms of diagnostic challenge or "tolerance tests"

- Insulin tolerance test for pituitary or adrenergic response assessment

- Protein challenge

- Leucine challenge

- Tolbutamide challenge

- Insulin potentiation therapy

- Insulin-induced coma for depression treatment

Lipoprotein lipase deficiency (also known as "familial chylomicronemia syndrome", "chylomicronemia", "chylomicronemia syndrome" and "hyperlipoproteinemia type Ia") is a rare autosomal recessive lipid disorder caused by a mutation in the gene which codes lipoprotein lipase. As a result, afflicted individuals lack the ability to produce lipoprotein lipase enzymes necessary for effective breakdown of triglycerides.

There are several genetic forms of hyperinsulinemic hypoglycemia:

Galactose epimerase deficiency, also known as GALE deficiency, Galactosemia III and UDP-galactose-4-epimerase deficiency, is a rare, autosomal recessive form of galactosemia associated with a deficiency of the enzyme "galactose epimerase".

Insulin dysregulation is commonly seen in horses with PPID or equine metabolic syndrome, and is associated with obesity. It is of interest primarily because of its link to laminitis. Horses with ID will have an increased insulin response after they are given oral sugars, which will cause a subsequent rise in blood insulin levels, or hyperinsulinemia. Hyperinsulinemia results in decreased tissue sensitivity to insulin, or insulin resistance especially by the skeletal muscle, liver and adipose tissue. Tissue insulin resistance causes increased insulin secretion, which perpetuates the cycle.

The trigger to insulin resistance is not fully understood. Genetics is likely to have some impact on the risk of postprandial hyperinsulinemia. Obesity, pregnancy, PPID, and inflammatory states may contribute to tissue insulin resistance. PPID is thought to result in increased insulin secretion due to higher levels of CLIP produced by melanotrophs, and to cause insulin resistance secondary to hyperadrenocorticism.

PPID shares similarities to Equine Metabolic Syndrome, which also causes regional adiposity, laminitis, and insulin resistance. Treatment and management may differ between the two endocrinopathies, making differentiation important. However, it is important to keep in mind that horses with EMS may develop PPID, therefore both diseases may occur simultaneously.

Individuals presenting with Type III galactosemia must consume a lactose- and galactose-restricted diet devoid of dairy products and mucilaginous plants. Dietary restriction is the only current treatment available for GALE deficiency. As glycoprotein and glycolipid metabolism generate endogenous galactose, however, Type III galactosemia may not be resolved solely through dietary restriction.

Insulinomas are rare neuroendocrine tumors with an incidence estimated at one to four new cases per million persons per year. Insulinoma is one of the most common types of tumors arising from the islets of Langerhans cells (pancreatic endocrine tumors). Estimates of malignancy (metastases) range from 5 to 30%. Over 99% of insulinomas originate in the pancreas, with rare cases from ectopic pancreatic tissue. About 5% of cases are associated with tumors of the parathyroid glands and the pituitary (multiple endocrine neoplasia type 1) and are more likely to be multiple and malignant. Most insulinomas are small, less than 2 cm.

Most patients with benign insulinomas can be cured with surgery. Persistent or recurrent hypoglycemia after surgery tends to occur in patients with multiple tumors. About 2% of patients develop diabetes mellitus after their surgery.

The presence of presenile cataract, noticeable in galactosemic infants as young as a few days old, is highly associated with two distinct types of galactosemia: GALT deficiency and to a greater extent, GALK deficiency.

An impairment or deficiency in the enzyme, galactose-1-phosphate uridyltransferase (GALT), results in classic galactosemia, or Type I galactosemia. Classic galactosemia is a rare (1 in 47,000 live births), autosomal recessive disease that presents with symptoms soon after birth when a baby begins lactose ingestion. Symptoms include life-threatening illnesses such as jaundice, hepatosplenomegaly (enlarged spleen and liver), hypoglycemia, renal tubular dysfunction, muscle hypotonia (decreased tone and muscle strength), sepsis (presence of harmful bacteria and their toxins in tissues), and cataract among others. The prevalence of cataract among classic galactosemics is markedly less than among galactokinase-deficient patients due to the extremely high levels of galactitol found in the latter. Classic galactosemia patients typically exhibit urinary galactitol levels of only 98 to 800 mmol/mol creatine compared to normal levels of 2 to 78 mmol/mol creatine.

Galactokinase (GALK) deficiency, or Type II galactosemia, is also a rare (1 in 100,000 live births), autosomal recessive disease that leads to variable galactokinase activity levels: ranging from high GALK efficiency to undetectably-low GALK efficiency. The early onset of cataract is the main clinical manifestation of Type II galactosemics, most likely due to the high concentration of galactitol found in this population. GALK deficient patients exposed to high-galactose diets show extreme levels of galactitol in blood and urine. Studies on galactokinase-deficient patients have shown that nearly two-thirds of ingested galactose can be accounted for by galactose and galactitol levels in the urine. Urinary levels of galactitol in these subjects approach 2500 mmol/mol creatine as compared to 2 to 78 mmol/mol creatine in control patients.

A decrease in activity in the third major enzymes of galactose metabolism, UDP galactose-4'-epimerase (GALE), is the cause of Type III galactosemia. GALE deficiency is an extremely rare, autosomal recessive disease that appears to be most common among the Japanese population (1 in 23,000 live births among Japanese population). While the link between GALE deficiency and cataract prevalence seems to be ambiguous, experiments on this topic have been conducted. A recent 2000 study in Munich, Germany analyzed the activity levels of the GALE enzyme in various tissues and cells in patients with cataract. The experiment concluded that while patients with cataract seldom exhibited an acute decrease in GALE activity in blood cells, "the GALE activity in the lens of cataract patients was, on the other hand, significantly decreased". The study's results are depicted below. The extreme decrease in GALE activity in the lens of cataract patients seems to suggest an irrefutable connection between Type III galactosemia and cataract development.

Galactosemia is one of the most mysterious of the heavily-researched metabolic diseases. It is a hereditary disease that results in a defect in, or absence of, galactose-metabolizing enzymes. This inborn error leaves the body unable to metabolize galactose, allowing toxic levels of galactose to build up in human body blood, cells, and tissues. Although treatment for galactosemic infants is a strict galactose-free diet, endogenous (internal) production of galactose can cause symptoms such as long-term morbidity, presenile development of cataract, renal failure, cirrhosis, and cognitive, neurologic, and female reproductive complications. Galactosemia used to be confused with diabetes due to the presence of sugar in a patient's urine. However, screening advancements have allowed the exact identity of those sugars to be determined, thereby distinguishing galactosemia from diabetes.

Prognosis is good, and treatment of this syndrome is usually unnecessary. Most patients are asymptomatic and have normal lifespans. Some neonates present with cholestasis. Hormonal contraceptives and pregnancy may lead to overt jaundice and icterus (yellowing of the eyes and skin).

The treatment for auto-brewery syndrome is a change in diet requiring low carbohydrates and high protein. Sugar is fermented into alcohol, and a diet that effectively lowers sugars also lowers the alcohol that can be fermented from it. Anything that causes an imbalance between the beneficial and harmful bacteria in the gut can help increase the chance that fermentation in the gut will develop. This can include not only antibiotics, but also overindulgence in sugars and carbohydrates. Watching what you eat could lower the risk of gut fermentation syndrome, and taking probiotics could further protect you by increasing the number of good bacteria in your system.

The treatment of nephrotic syndrome can be symptomatic or can directly address the injuries caused to the kidney.

Dubin–Johnson syndrome (DJS) is a rare, autosomal recessive, benign disorder that causes an isolated increase of conjugated bilirubin in the serum. Classically, the condition causes a black liver due to the deposition of a pigment similar to melanin. This condition is associated with a defect in the ability of hepatocytes to secrete conjugated bilirubin into the bile, and is similar to Rotor syndrome. It is usually asymptomatic, but may be diagnosed in early infancy based on laboratory tests. No treatment is usually needed.

The mortality rate for THAN is relatively high unless immediate treatment is obtained. The duration of hyperammonemia is directly correlated to morbidity as well as the associated neurological conditions. After the first hyperammonemic episode, there is no increased risk for future hyperammonemic episodes, and normal protein consumption can be continued.

The effects of the disease can have profound effects on everyday life. As well, the recurring side effects of excessive belching, dizziness, dry mouth, hangovers, disorientation, irritable bowel syndrome, and chronic fatigue syndrome can lead to other health problems such as depression, anxiety and poor productivity in employment. The random state of intoxication can lead to personal difficulties, and the relative obscurity of the condition can also make it hard to seek treatment.

Nephrotic syndrome can be associated with a series of complications that can affect an individual’s health and quality of life:

- Thromboembolic disorders: particularly those caused by a decrease in blood antithrombin III levels due to leakage. Antithrombin III counteracts the action of thrombin. Thrombosis usually occurs in the renal veins although it can also occur in arteries. Treatment is with oral anticoagulants (not heparin as heparin acts via anti-thrombin 3 which is lost in the proteinuria so it will be ineffective.) Hypercoagulopathy due to extravasation of fluid from the blood vessels (edema) is also a risk for venous thrombosis.

- Infections: The increased susceptibility of patients to infections can be a result of the leakage of immunoglobulins from the blood, the loss of proteins in general and the presence of oedematous fluid (which acts as a breeding ground for infections). The most common infection is peritonitis, followed by lung, skin and urinary infections, meningoencephalitis and in the most serious cases septicaemia. The most notable of the causative organisms are "Streptococcus pneumoniae" and "Haemophilus influenzae".

- Acute kidney failure due to hypovolemia: the loss of vascular fluid into the tissues (edema) produces a decreased blood supply to the kidneys that causes a loss of kidney function. Thus it is a tricky task to get rid of excess fluid in the body while maintaining circulatory euvolemia.

- Pulmonary edema: the loss of proteins from blood plasma and the consequent fall in oncotic pressure causes an abnormal accumulation of liquid in the lungs causing hypoxia and dyspnoea.

- Hypothyroidism: deficiency of the thyroglobulin transport protein thyroxin (a glycoprotein that is rich in iodine and is found in the thyroid gland) due to decreased thyroid binding globulin.

- Hypocalcaemia: lack of 25-hydroxycholecalciferol (the way that vitamin D is stored in the body). As vitamin D regulates the amount of calcium present in the blood a decrease in its concentration will lead to a decrease in blood calcium levels. It may be significant enough to cause tetany. Hypocalcaemia may be relative; calcium levels should be adjusted based on the albumin level and ionized calcium levels should be checked.

- Microcytic hypochromic anaemia: iron deficiency caused by the loss of ferritin (compound used to store iron in the body). It is iron-therapy resistant.

- Protein malnutrition: this occurs when the amount of protein that is lost in the urine is greater than that ingested, this leads to a negative nitrogen balance.

- Growth retardation: can occur in cases of relapse or resistance to therapy. Causes of growth retardation are protein deficiency from the loss of protein in urine, anorexia (reduced protein intake), and steroid therapy (catabolism).

- Vitamin D deficiency can occur. Vitamin D binding protein is lost.

- Cushing's Syndrome

A study was done by Hudak to find the differences between transient hyperammonemia of the newborn (THAN) and urea cycle enzyme deficiency(UCED) on 33 THAN victims and 13 UCED victims. Some of the clinical findings were not able to be measured in the THAN patients due to lack of equipment or lack of reported information in these 33 cases, so the numbers shown represent the number of positive clinical findings/out of the number cases in which the symptom could be observed or was documented. The results were as follows:

Respiratory distress occurred in 22/23 of THAN patients and only in 0/13 of UCED patients. Abnormal chest radiographs were found in 23/25 THAN victims, and 0/9 in UCED patients. The gestational age was less than 36 weeks in 25/31 THAN patients, but only 1/13 UCED patients. The birthweight was less than 2.5 kg in 27/31 THAN patients and in 2/12 UCED patients. A coma that lasted 48 hours or longer occurred in 12/17 THAN patients but only occurred in 1/12 UCED patients. Free ammonia (NH4+) levels greater than 1500 µM occurred in 17/29 THAN patients but only 1/13 UCED patients.

Acute intermittent porphyria (AIP) is a genetic metabolic disorder affecting the production of heme, the oxygen-binding prosthetic group of hemoglobin. It is characterized by a deficiency of the enzyme porphobilinogen deaminase. Its inheritance is more commonly autosomal dominant; however, autosomal recessive forms of this disorder have occurred. Its incidence is estimated to be between 5 and 10 in 100,000.

Most of the etiologic considerations regarding senile osteoporosis are not very clear for physicians yet. But based on the current evidence attached to clinical experimentation, it has been determined that the pathogenesis of the disease is clearly related to a deficiency of zinc. Such deficiency is known to lead to an increment of endogenous heparin, which is most likely caused by mast cell degranulation, and an increase in the bone resorption (calcium discharge in the bones) reaction of prostaglandin E2, which constrain the formation of more bone mass, making bones more fragile. These co-factors are shown to play an important role in the pathogenetic process attached to senile osteoporosis as they enhance the action of the parathyroid hormone.

The intake of calcium in elder people is quite low, and this problem is worsened by a reduced capability to ingest it. This, attached to a decrease in the absorption of vitamin D concerning metabolism, are also factors that contributes to a diagnosis of osteoporosis type II.

Senile osteoporosis, formerly known as osteoporosis type II, has been recently recognized as a geriatric syndrome with a particular pathophysiology.

It has been pointed out that senile osteoporosis is the product of a skeleton in an advanced stage of life and also due to a deficiency caused by calcium, but physicians are also coming to the conclusion that multiple mechanisms in the development stages of the disease interact together and the product is an osteoporotic bone, regardless of age.

Netherton syndrome is a severe, autosomal recessive form of ichthyosis associated with mutations in the "SPINK5" gene. It is named after Earl W. Netherton (1910–1985), an American dermatologist who discovered it in 1958.

Endocrine disorder is more common in women than men, as it is associated with menstrual disorders.