Succinyl-CoA:3-oxoacid CoA transferase deficiency (SCOT deficiency) is an inborn error of ketone body utilization. Succinyl-CoA:3-oxoacid CoA transferase catalyzes the transfer of coenzyme A from succinyl-coenzyme A to acetoacetate. It can be caused by mutation in the "OXCT1" gene.

First described in 1972, more than 30 people have been reported in the medical literature with this inborn error of metabolism. They experience attacks of ketoacidosis during illness, and even when unwell may have elevated levels of ketone bodies in blood and urine (ketonemia and ketonuria, respectively). Not all people with SCOT deficiency have persistent ketonemia and ketonuria, particularly those with milder defects of enzyme activity.

Symptoms of congenital Type III Galactosemia are apparent from birth, but vary in severity depending on whether the peripheral or generalized disease form is present. Symptoms may include:

- Infantile jaundice

- Infantile hypotonia

- Dysmorphic features

- Sensorineural hearing loss

- Impaired growth

- Cognitive deficiencies

- Depletion of cerebellar Purkinje cells

- Ovarian failure (POI) and hypertrophic hypergonadism

- Liver failure

- Renal failure

- Splenomegaly

- Cataracts

Studies of Type III galactosemia symptoms are mostly descriptive, and precise pathogenic mechanisms remain unknown. This is largely due to a lack of functional animal models of classic galactosemia. The recent development of a "Drosophila melanogaster" GALE mutant exhibiting galactosemic symptoms may yield a promising future animal model.

The signs and symptoms of beta-ketothiolase deficiency include vomiting, dehydration, trouble breathing, extreme tiredness, and occasionally convulsions. These episodes are called ketoacidotic attacks and can sometimes lead to coma. Attacks occur when compounds called organic acids (which are formed as products of amino acid and fat breakdown) build up to toxic levels in the blood. These attacks are often triggered by an infection, fasting (not eating), or in some cases, other types of stress.

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".

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.

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.

Beta-ketothiolase deficiency is a rare, autosomal recessive metabolic disorder in which the body cannot properly process the amino acid isoleucine or the products of lipid breakdown.

The typical age of onset for this disorder is between 6 months and 24 months.

Infants with this disease seem healthy at birth but quickly deteriorate, often with severe brain damage, which may be permanent. Death often occurs within the first five months in severe cases of the disease, when left untreated.

The symptoms of MSUD may also present later depending on the severity of the disease. Untreated in older individuals, and during times of metabolic crisis, symptoms of the condition include uncharacteristically inappropriate, extreme or erratic behaviour and moods, hallucinations, anorexia, weight loss, anemia, diarrhea, vomiting, dehydration, lethargy, oscillating hypertonia and hypotonia, ataxia, seizures, hypoglycaemia, ketoacidosis, opisthotonus, pancreatitis, rapid neurological decline, and coma. Without prompt treatment, they will likely die from cerebral edema. Additionally, maple syrup urine disease patients often experience an abnormal course of disease in simple infections that become increasingly severe and can have permanent damage. In more rare cases, concomitant osteoporosis may also appear in these patients.

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.

Some patients suffering from copper deficiency have shown signs of vision and color loss. The vision is usually lost in the peripheral views of the eye. The bilateral vision loss is usually very gradual. An optical coherence tomography (OCT) shows some nerve fiber layer loss in most patients, suggesting the vision loss and color vision loss was secondary to optic neuropathy or neurodegeneration.

Symptoms of the familial form include visual impairment caused by diffuse corneal opacities, target cell hemolytic anemia, and renal failure. Less common symptoms include atherosclerosis, hepatomegaly (enlarged liver), splenomegaly (enlarged spleen), and lymphadenopathy.

Fish-eye disease is less severe and most commonly presents with impaired vision due to corneal opacification. It rarely presents with other findings, although, atherosclerosis, hepatomegaly, splenomegaly, and lymphadenopathy can occur. Carlson and Philipson found that the disease was named so because the cornea of the eye was so opaque or cloudy with dots of cholesterol that it resembled a boiled fish.

If an individual only carry one copy of the mutated gene, they typically do not show symptoms.

Organic acidemias are usually diagnosed in infancy, characterized by urinary excretion of abnormal amounts or types of organic acids. The diagnosis is usually made by detecting an abnormal pattern of organic acids in a urine sample by gas chromatography-mass spectrometry. In some conditions, the urine is always abnormal, in others the characteristic substances are only present intermittently. Many of the organic acidemias are detectable by newborn screening with tandem mass spectrometry.

These disorders vary in their prognosis, from manageable to fatal, and usually affect more than one organ system, especially the central nervous system.

Neurological damage and developmental delay are common factors in diagnosis, with associated symptoms ranging from poor feeding to slow growth, lethargy, vomiting,

dehydration, malnutrition, hypoglycemia, hypotonia, metabolic acidosis, ketoacidosis, hyperammonemia, and if left untreated, death.

Lecithin cholesterol acyltransferase deficiency (LCAT deficiency) is a disorder of lipoprotein metabolism. The disease has two forms: Familial LCAT deficiency, in which there is complete LCAT deficiency, and Fish-eye disease, in which there is a partial deficiency.

Lecithin cholesterol acyltransferase catalyzes the formation of cholesterol esters in lipoproteins.

Organic acidemia, also called organic aciduria, is a term used to classify a group of metabolic disorders which disrupt normal amino acid metabolism, particularly branched-chain amino acids, causing a buildup of acids which are usually not present.

The branched-chain amino acids include isoleucine, leucine and valine. Organic acids refer to the amino acids and certain odd-chained fatty acids which are affected by these disorders.

The four main types of organic acidemia are: methylmalonic acidemia, propionic acidemia, isovaleric acidemia, and maple syrup urine disease.

The following list includes such examples:

- - hyperammonemia due to ornithine transcarbamylase deficiency

- - hyperinsulinism-hyperammonemia syndrome (glutamate dehydrogenase 1)

- - hyperornithinemia-hyperammonemia-homocitrullinuria

- - hyperammonemia due to N-acetylglutamate synthetase deficiency

- - hyperammonemia due to carbamoyl phosphate synthetase I deficiency (carbamoyl phosphate synthetase I)

- - hyperlysinuria with hyperammonemia (genetics unknown)

- Methylmalonic acidemia

- Isovaleric acidemia

- Propionic acidemia

- Carnitine palmitoyltransferase II deficiency

- Transient hyperammonemia of the newborn, specifically in the preterm

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.

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.

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.

Folate deficiency is a low level of folic acid and derivatives in the body. Also known as vitamin B9, folate is involved in adenosine, guanine, and thymidine synthesis (part of DNA synthesis). Signs of folate deficiency are often subtle. Anemia is a late finding in folate deficiency and folate deficiency anemia is the term given for this medical condition. It is characterized by the appearance of large-sized, abnormal red blood cells (megaloblasts), which form when there are inadequate stores of folic acid within the body.

A vitamin deficiency can cause a disease or syndrome known as an avitaminosis or hypovitaminosis. This usually refers to a long-term deficiency of a vitamin. When caused by inadequate nutrition it can be classed as a "primary deficiency", and when due to an underlying disorder such as malabsorption it can be classed as a "secondary deficiency". An underlying disorder may be metabolic as in a defect converting tryptophan to niacin. It can also be the result of lifestyle choices including smoking and alcohol consumption.

Examples are vitamin A deficiency, folate deficiency, scurvy, vitamin D deficiency, vitamin E deficiency, and vitamin K deficiency. In the medical literature, any of these may also be called by names on the pattern of "hypovitaminosis" or "avitaminosis" + "[letter of vitamin]", for example, hypovitaminosis A, hypovitaminosis C, hypovitaminosis D.

Conversely hypervitaminosis is the syndrome of symptoms caused by over-retention of fat-soluble vitamins in the body.

- Vitamin A deficiency can cause keratomalacia.

- Thiamine (vitamin B1) deficiency causes beriberi and Wernicke–Korsakoff syndrome.

- Riboflavin (vitamin B2) deficiency causes ariboflavinosis.

- Niacin (vitamin B3) deficiency causes pellagra.

- Pantothenic acid (vitamin B5) deficiency causes chronic paresthesia.

- Vitamin B6

- Biotin (vitamin B7) deficiency negatively affects fertility and hair/skin growth. Deficiency can be caused by poor diet or genetic factors (such as mutations in the BTD gene, see multiple carboxylase deficiency).

- Folate (vitamin B9) deficiency is associated with numerous health problems. Fortification of certain foods with folate has drastically reduced the incidence of neural tube defects in countries where such fortification takes place. Deficiency can result from poor diet or genetic factors (such as mutations in the MTHFR gene that lead to compromised folate metabolism).

- Vitamin B12 (cobalamin) deficiency can lead to pernicious anemia, megaloblastic anemia, subacute combined degeneration of spinal cord, and methylmalonic acidemia among other conditions.

- Vitamin C (ascorbic acid) short-term deficiency can lead to weakness, weight loss and general aches and pains. Longer-term depletion may affect the connective tissue. Persistent vitamin C deficiency leads to scurvy.

- Vitamin D (cholecalciferol) deficiency is a known cause of rickets, and has been linked to numerous health problems.

- Vitamin E deficiency causes nerve problems due to poor conduction of electrical impulses along nerves due to changes in nerve membrane structure and function.

- Vitamin K (phylloquinone or menaquinone) deficiency causes impaired coagulation and has also been implicated in osteoporosis

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.

Severe zinc deficiency may disturb the sense of smell and taste. Night blindness may be a feature of severe zinc deficiency, however most reports of night blindness and abnormal dark adaptation in humans with zinc deficiency have occurred in combination with other nutritional deficiencies (e.g. vitamin A).

Zinc deficiency may manifest as acne, eczema, xerosis (dry, scaling skin), seborrheic dermatitis, or alopecia (thin and sparse hair). There may also be impaired wound healing.