Often symptoms will arise that indicate the body is not absorbing or making the lipoproteins that it needs. These symptoms usually appear "en masse", meaning that they happen all together, all the time. These symptoms come as follows:

- Failure to thrive/Failure to grow in infancy

- Steatorrhea/Fatty, pale stools

- Frothy stools

- Foul smelling stools

- Protruding abdomen

- Intellectual disability/developmental delay

- Developmental coordination disorder, evident by age ten

- Muscle weakness

- Slurred speech

- Scoliosis (curvature of the spine)

- Progressive decreased vision

- Balance and coordination problems

Abetalipoproteinemia affects the absorption of dietary fats, cholesterol, and certain vitamins. People affected by this disorder are not able to make certain lipoproteins, which are molecules that consist of proteins combined with cholesterol and particular fats called triglycerides. This leads to a multiple vitamin deficiency, affecting the fat-soluble vitamin A, vitamin D, vitamin E, and vitamin K. However, many of the observed effects are due to vitamin E deficiency in particular.

The signs and symptoms of abetalipoproteinemia appear in the first few months of life (because pancreatic lipase is not active in this period). They can include failure to gain weight and grow at the expected rate (failure to thrive); diarrhea; abnormal spiny red blood cells (acanthocytosis); and fatty, foul-smelling stools (steatorrhea). The stool may contain large chunks of fat and/or blood. Other features of this disorder may develop later in childhood and often impair the function of the nervous system. They can include poor muscle coordination, difficulty with balance and movement (ataxia), and progressive degeneration of the retina (the light-sensitive layer in the posterior eye) that can progress to near-blindness (due to deficiency of vitamin A, retinol). Adults in their thirties or forties may have increasing difficulty with balance and walking. Many of the signs and symptoms of abetalipoproteinemia result from a severe vitamin deficiency, especially vitamin E deficiency, which typically results in eye problems with degeneration of the spinocerebellar and dorsal column tracts.

Hypobetalipoproteinemia is a disorder consisting of low levels of LDL cholesterol or apolipoprotein B, below the 5th percentile. The patient can have hypobetalipoproteinemia and simultaneously have high levels of HDL cholesterol.

Notably, in people who do not have the genetic disorder hypobetalipoproteinemia, a low cholesterol level may be a marker for poor nutrition, wasting disease, cancer, hyperthyroidism, and liver disease.

Typically in hypobetalipoproteinemia, plasma cholesterol levels will be around 80–120 mg/dL, LDL cholesterol will be around 50–80 mg/dL.

According to the American Heart Association in 1994, only total cholesterol levels below 160 mg/dL or 4.1 mmol/l are to be classified as "hypocholesterolemia". However, this is not agreed on universally and some put the level lower.

Possible causes of low cholesterol are:

- statins

- hyperthyroidism, or an overactive thyroid gland

- adrenal insufficiency

- liver disease

- malabsorption (inadequate absorption of nutrients from the intestines), such as in celiac disease

- malnutrition

- abetalipoproteinemia - a rare genetic disease that causes cholesterol readings below 50 mg/dl. It is found mostly in Jewish populations.

- hypobetalipoproteinemia - a genetic disease that causes cholesterol readings below 50 mg/dl

- manganese deficiency

- Smith-Lemli-Opitz syndrome

- Marfan syndrome

- leukemias and other hematological diseases

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 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.

Fatty liver is a reversible condition wherein large vacuoles of triglyceride fat accumulate in liver cells via the process of steatosis (i.e., abnormal retention of lipids within a cell). Despite having multiple causes, fatty liver can be considered a single disease that occurs worldwide in those with excessive alcohol intake and the obese (with or without effects of insulin resistance). The condition is also associated with other diseases that influence fat metabolism. When this process of fat metabolism is disrupted, the fat can accumulate in the liver in excessive amounts, thus resulting in a fatty liver. It is difficult to distinguish alcoholic FLD, which is part of alcoholic liver disease, from nonalcoholic FLD (NAFLD), and both show microvesicular and macrovesicular fatty changes at different stages.

The accumulation of fat in alcoholic or non-alcoholic steatosis may also be accompanied by a progressive inflammation of the liver (hepatitis), called steatohepatitis. This more severe condition may be termed either alcoholic steatohepatitis or non-alcoholic steatohepatitis (NASH).

Fatty liver (FL) is commonly associated with alcohol or metabolic syndrome (diabetes, hypertension, obesity, and dyslipidemia), but can also be due to any one of many causes:

- Metabolic: abetalipoproteinemia, glycogen storage diseases, Weber–Christian disease, acute fatty liver of pregnancy, lipodystrophy

- Nutritional:malnutrition, total parenteral nutrition, severe weight loss, refeeding syndrome, jejunoileal bypass, gastric bypass, jejunal diverticulosis with bacterial overgrowth

- Drugs and toxins: amiodarone, methotrexate, diltiazem, expired tetracycline, highly active antiretroviral therapy, glucocorticoids, tamoxifen, environmental hepatotoxins (e.g., phosphorus, mushroom poisoning)

- Alcohol: Alcoholism is one of the major causes of fatty liver due to production of toxic metabolites like aldehydes during metabolism of alcohol in the liver. This phenomenon most commonly occurs with chronic alcoholism.

- Other: celiac disease, inflammatory bowel disease, HIV, hepatitis C (especially genotype 3), and alpha 1-antitrypsin deficiency

An "Addisonian crisis" or "adrenal crisis" is a constellation of symptoms that indicates severe adrenal insufficiency. This may be the result of either previously undiagnosed Addison's disease, a disease process suddenly affecting adrenal function (such as adrenal hemorrhage), or an intercurrent problem (e.g., infection, trauma) in someone known to have Addison's disease. It is a medical emergency and potentially life-threatening situation requiring immediate emergency treatment.

Characteristic symptoms are:

- Sudden penetrating pain in the legs, lower back, or abdomen

- Severe vomiting and diarrhea, resulting in dehydration

- Low blood pressure

- Syncope (loss of consciousness and ability to stand)

- Hypoglycemia (reduced level of blood glucose)

- Confusion, psychosis, slurred speech

- Severe lethargy

- Hyponatremia (low sodium level in the blood)

- Hyperkalemia (elevated potassium level in the blood)

- Hypercalcemia (elevated calcium level in the blood)

- Convulsions

- Fever

Signs and symptoms include: hypoglycemia, dehydration, weight loss, and disorientation. Additional signs and symptoms include weakness, tiredness, dizziness, low blood pressure that falls further when standing (orthostatic hypotension), cardiovascular collapse, muscle aches, nausea, vomiting, and diarrhea. These problems may develop gradually and insidiously. Addison's disease can present with tanning of the skin that may be patchy or even all over the body. Characteristic sites of tanning are skin creases (e.g. of the hands) and the inside of the cheek (buccal mucosa). Goitre and vitiligo may also be present. Eosinophilia may also occur.

The initial retinal degenerative symptoms of retinitis pigmentosa are characterized by decreased night vision (nyctalopia) and the loss of the mid-peripheral visual field. The rod photoreceptor cells, which are responsible for low-light vision and are orientated in the retinal periphery, are the retinal processes affected first during non-syndromic forms of this disease. Visual decline progresses relatively quickly to the far peripheral field, eventually extending into the central visual field as tunnel vision increases. Visual acuity and color vision can become compromised due to accompanying abnormalities in the cone photoreceptor cells, which are responsible for color vision, visual acuity, and sight in the central visual field. The progression of disease symptoms occurs in a symmetrical manner, with both the left and right eyes experiencing symptoms at a similar rate.

A variety of indirect symptoms characterize retinitis pigmentosa along with the direct effects of the initial rod photoreceptor degeneration and later cone photoreceptor decline. Phenomena such as photophobia, which describes the event in which light is perceived as an intense glare, and photopsia, the presence of blinking or shimmering lights within the visual field, often manifest during the later stages of RP. Findings related to RP have often been characterized in the fundus of the eye as the "ophthalamic triad". This includes the development of (1) a mottled appearance of the retinal pigment epithelium (RPE) caused by bone spicule formation, (2) a waxy appearance of the optic nerve, and (3) the attentuation of blood vessels in the retina.

Non-syndromic RP usually presents a variety of the following symptoms:

- Night blindness

- Tunnel vision (due to loss of peripheral vision)

- Latticework vision

- Photopsia (blinking/shimmering lights)

- Photophobia (aversion to glare)

- Development of bone spicules in the fundus

- Slow adjustment from dark to light environments and vice versa

- Blurring of vision

- Poor color separation

- Loss of central vision

- Eventual blindness

Adrenal insufficiency is a condition in which the adrenal glands do not produce adequate amounts of steroid hormones, primarily cortisol; but may also include impaired production of aldosterone (a mineralocorticoid), which regulates sodium conservation, potassium secretion, and water retention. Craving for salt or salty foods due to the urinary losses of sodium is common.

Addison's disease and congenital adrenal hyperplasia can manifest as adrenal insufficiency. If not treated, adrenal insufficiency may result in severe abdominal pains, vomiting, profound muscle weakness and fatigue, depression, extremely low blood pressure (hypotension), weight loss, kidney failure, changes in mood and personality, and shock (adrenal crisis). An adrenal crisis often occurs if the body is subjected to stress, such as an accident, injury, surgery, or severe infection; death may quickly follow.

Adrenal insufficiency can also occur when the hypothalamus or the pituitary gland does not make adequate amounts of the hormones that assist in regulating adrenal function. This is called secondary or tertiary adrenal insufficiency and is caused by lack of production of ACTH in the pituitary or lack of CRH in the hypothalamus, respectively.

Causes of adrenal insufficiency can be categorized by the mechanism through which they cause the adrenal glands to produce insufficient cortisol. These are adrenal dysgenesis (the gland has not formed adequately during development), impaired steroidogenesis (the gland is present but is biochemically unable to produce cortisol) or adrenal destruction (disease processes leading to glandular damage).

RP may be:

(1) Non-syndromic, that is, it occurs alone, without any other clinical findings,

(2) Syndromic, with other neurosensory disorders, developmental abnormalities, or complex clinical findings, or

(3) Secondary to other systemic diseases.

- RP combined with deafness (congenital or progressive) is called Usher syndrome.

- Alport's syndrome is associated with RP and an abnormal glomerular-basement membrane leading nephrotic syndrome and inherited as X-linked dominant.

- RP combined with ophthalmoplegia, dysphagia, ataxia, and cardiac conduction defects is seen in the mitochondrial DNA disorder Kearns-Sayre syndrome (also known as Ragged Red Fiber Myopathy)

- RP combined with retardation, peripheral neuropathy, acanthotic (spiked) RBCs, ataxia, steatorrhea, is absence of VLDL is seen in abetalipoproteinemia.

- RP is seen clinically in association with several other rare genetic disorders (including muscular dystrophy and chronic granulomatous disease) as part of McLeod syndrome. This is an X-linked recessive phenotype characterized by a complete absence of XK cell surface proteins, and therefore markedly reduced expression of all Kell red blood cell antigens. For transfusion purposes these patients are considered completely incompatible with all normal and K0/K0 donors.

- RP associated with hypogonadism, and developmental delay with an autosomal recessive inheritance pattern is seen with Bardet-Biedl syndrome

Other conditions include neurosyphilis, toxoplasmosis and Refsum's disease.

Sydenham's chorea (SC) or chorea minor (historically referred to as St Vitus's dance) is a disorder characterized by rapid, uncoordinated jerking movements primarily affecting the face, hands and feet. Sydenham's chorea results from childhood infection with Group A beta-haemolytic "Streptococcus" and is reported to occur in 20–30% of patients with acute rheumatic fever (ARF). The disease is usually latent, occurring up to 6 months after the acute infection, but may occasionally be the presenting symptom of rheumatic fever. Sydenham's chorea is more common in females than males and most patients are children, below 18 years of age. Adult onset of Sydenham's chorea is comparatively rare and the majority of the adult cases are associated with exacerbation of chorea following childhood Sydenham's chorea.

Sydenham's chorea is characterized by the abrupt onset (sometimes within a few hours) of neurologic symptoms, classically chorea, usually affecting all four limbs. Other neurologic symptoms include behavior change, dysarthria, gait disturbance, loss of fine and gross motor control with resultant deterioration of handwriting, headache, slowed cognition, facial grimacing, fidgetiness and hypotonia. Also, there may be tongue fasciculations ("bag of worms") and a "milk sign", which is a relapsing grip demonstrated by alternate increases and decreases in tension, as if hand milking.

Non-neurologic manifestations of acute rheumatic fever are carditis, arthritis, erythema marginatum, and subcutaneous nodules.

The PANDAS (pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections) syndrome is similar, but is not characterized by Sydenham's motor dysfunction. PANDAS presents with tics and/or a psychological component (e.g., OCD) and occurs much earlier, days to weeks after GABHS infection rather than 6–9 months later. It may be confused with other conditions such as lupus and Tourette syndrome.

Movements cease during sleep, and the disease usually resolves after several months. Unlike in Huntington's disease, which is generally of adult onset and associated with an unremitting autosomal dominant movement disorder and dementia, neuroimaging in Sydenham's chorea is normal and other family members are unaffected. Other disorders that may be accompanied by chorea include abetalipoproteinemia, ataxia-telangiectasia, biotin-thiamine-responsive basal ganglia disease, Fahr disease, familial dyskinesia-facial myokymia (Bird-Raskind syndrome) due to an ADCY5 gene mutation, glutaric aciduria, Lesch-Nyhan syndrome, mitochondrial disorders, Wilson disease, hyperthyroidism, lupus erythematosus, pregnancy (chorea gravidarum), and side effects of certain anticonvulsants or psychotropic agents.