The main symptoms of ADA deficiency are pneumonia, chronic diarrhea, and widespread skin rashes. Affected children also grow much more slowly than healthy children and some have developmental delay. Most individuals with ADA deficiency are diagnosed with SCID in the first 6 months of 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.

Adenosine deaminase deficiency (also called ADA deficiency or ADA-SCID) is an autosomal recessive metabolic disorder that causes immunodeficiency. It occurs in fewer than one in 100,000 live births worldwide.

It accounts for about 15% of all cases of severe combined immunodeficiency (SCID).

ADA deficiency may be present in infancy, childhood, adolescence, or adulthood. Age of onset and severity is related to some 29 known genotypes associated with the disorder.

Among the signs and symptoms of adenylosuccinate lyase deficiency are the following:

- Aggressive behavior

- Microcephaly

- Autism

- Brachycephaly

- Mild Cerebellar hypoplasia

- Seizures

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.

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

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

Mevalonate kinase deficiency, also called mevalonic aciduria and hyper immunoglobin D syndrome is an autosomal recessive metabolic disorder that disrupts the biosynthesis of cholesterol and isoprenoids.

It is characterized by an elevated level of immunoglobin D in the blood.

The enzyme is involved in biosynthesis of cholesterols and isoprenoids. The enzyme is necessary for the conversion of mevalonate to mevalonate-5-phosphate in the presence of Mg2+ [Harper’s biochemistry manual]. Mevalonate kinase deficiency causes the accumulation of mevalonate in urine and hence the activity of the enzyme is again reduced Mevalonate kinase deficiency. It was first described as HIDS in 1984.

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.

Adenylosuccinate lyase deficiency, also called adenylosuccinase deficiency, is a rare autosomal recessive metabolic disorder characterized by the appearance of succinylaminoimidazolecarboxamide riboside (SAICA riboside) and succinyladenosine (S-Ado) in cerebrospinal fluid, urine.These two succinylpurines are the dephosphorylated derivatives of SAICA ribotide (SAICAR) and adenylosuccinate (S-AMP), the two substrates of adenylosuccinate lyase (ADSL), which catalyzes an important reaction in the de novo pathway of purine biosynthesis. ADSL catalyzes two distinct reactions in the synthesis of purine nucleotides, both of which involve the β-elimination of fumarate to produce aminoimidazole carboxamide ribotide (AICAR) from SAICAR or adenosine monophosphate (AMP) from S-AMP.

In undiagnosed and untreated children, the accumulation of precursor metabolites due to the deficient activity of galactose 1-phosphate uridylyltransferase (GALT) can lead to feeding problems, failure to thrive, liver damage, bleeding, and infections. The first presenting symptom in an infant is often prolonged jaundice. Without intervention in the form of galactose restriction, infants can develop hyperammonemia and sepsis, possibly leading to shock. The accumulation of galactitol and subsequent osmotic swelling can lead to cataracts which are similar to those seen in galactokinase deficiency. Long-term consequences of continued galactose intake can include developmental delay, developmental verbal dyspraxia, and motor abnormalities. Galactosemic females frequently suffer from ovarian failure, regardless of treatment in the form of galactose restriction.

Diagnosis of Molybdenum cofactor deficiency includes early seizures, low blood levels of uric acid, and high levels of sulphite, xanthine, and uric acid in urine. Additionally, the disease produces characteristic MRI images that can aid in diagnosis.

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".

Molybdenum cofactor deficiency is a rare human disease in which the absence of molybdenum cofactor leads to accumulation of toxic levels of sulphite and neurological damage. Usually this leads to death within months of birth, due to the lack of active sulfite oxidase. Furthermore, a mutational block in molybdenum cofactor biosynthesis causes absence of enzyme activity of xanthine dehydrogenase/oxidase and aldehyde oxidase.

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.

Galactose-1-phosphate uridylyltransferase deficiency, also called galactosemia type 1, classic galactosemia or GALT deficiency, is the most common type of galactosemia, an inborn error of galactose metabolism, caused by a deficiency of the enzyme galactose-1-phosphate uridylyltransferase. It is an autosomal recessive metabolic disorder that can cause liver disease and death if untreated. Treatment of galactosemia is most successful if initiated early and includes dietary restriction of lactose intake. Because early intervention is key, galactosemia is included in newborn screening programs in many areas. On initial screening, which often involves measuring the concentration of galactose in blood, classic galactosemia may be indistinguishable from other inborn errors of galactose metabolism, including galactokinase deficiency and galactose epimerase deficiency. Further analysis of metabolites and enzyme activities are needed to identify the specific metabolic error.

Mevalonate kinase deficiency causes an accumulation of mevalonic acid in the urine, resulting from insufficient activity of the enzyme mevalonate kinase (ATP:mevalonate 5-phosphotransferase; EC 2.7.1.36).

The disorder was first described in 1985.

Classified as an inborn error of metabolism, mevalonate kinase deficiency usually results in developmental delay, hypotonia, anemia, hepatosplenomegaly, various dysmorphic features, mental retardation, an overall failure to thrive and several other features.

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.

Signs and symptoms of AIP can be variable. Severe and poorly localized abdominal pain is a very common symptom (found in 95% of those affected by AIP). Urinary signs and symptoms such as painful urination, urinary retention, urinary incontinence, or dark urine have also been known to occur. Psychiatric signs and symptoms of AIP may manifest as anxiety, paranoia, irritability, delusions, hallucinations, confusion, and depression. Signs that suggest increased activity of the sympathetic nervous system may be evident including tachycardia, hypertension, palpitations, orthostatic hypotension, sweating, restlessness, and tremor. Other neurologic signs and symptoms of AIP include seizures, peripheral neuropathy, abnormal sensations, chest pain, leg pain, back pain or headache, and coma. Nausea, vomiting, constipation, and diarrhea can also occur. Proximal muscle weakness typically beginning in the arms is characteristic; there can be muscle pain, tingling, numbness, weakness or paralysis; muscle weakness seen in AIP can progress to include the muscles of breathing causing respiratory failure and can be fatal.

AIP patients have an increased risk of developing hepatocellular carcinoma, melanoma, lymphoma, chronic hypertension, chronic kidney disease, and chronic pain.

Its hereditary form, an autosomal recessive disorder, can be caused by a deficiency in the enzyme UMPS, a bifunctional protein that includes the enzyme activities of orotate phosphoribosyltransferase and orotidine 5'-phosphate decarboxylase.

It can also arise secondary to blockage of the urea cycle, particularly in ornithine transcarbamylase deficiency (or OTC deficiency). This can be distinguished from hereditary orotic aciduria (seen above) by assessing blood ammonia levels and blood urea nitrogen (BUN). In OTC deficiency, hyperammonemia and decreased BUN are seen because the urea cycle is not functioning properly.

Adenosine monophosphate deaminase deficiency type 1, also called myoadenylate deaminase deficiency (MADD), is a recessive genetic metabolic disorder that affects approximately 1–2% of populations of European descent. It appears to be considerably rarer in Asian populations. The genetic form is caused by a defect in the gene for AMP deaminase though there is also an acquired form of AMP deficiency.

Although many people with a defective AMPD gene are asymptomatic, others may have symptoms such as exercise intolerance, muscle pain, and muscle cramping.

- Fatigue

- MADD lowers aerobic power output, so increased anaerobic power is needed to perform the same amount of work.

- Without myoadenlyate deaminase, heavy activity causes adenosine to be released into the cell or perfused into the surrounding tissues. Fatigue and sedation after heavy exertion can be caused by excess adenosine in the cells which signals muscle fiber to feel fatigued. In the brain, excess adenosine decreases alertness and causes sleepiness. In this way, adenosine may play a role in fatigue from MADD.

- Recovery from over-exertion can be hours, days or even months. In cases of rhabdomyolysis, which is the rapid breakdown of muscle fibers, time to recovery is dependent on duration and intensity of original activity plus any excess activity during the recovery period.

- Muscle pain

- Muscle pain from MADD is not well understood, but is partially due to high levels of lactate. Increased levels of free adenosine temporarily decrease pain, allowing over-exertion without awareness. The over exertion can cause mild to severe cases of rhabdomyolysis, which is painful.

- Adenosine mediates pain through adenosine receptors. MADD causes an increase of free adenosine during heavy activity which may cause exercise-induced muscle pain. Over time, excess free adenosine down-regulates primary A1 adenosine receptors, leading to increased muscle pain. Secondary receptors (A3) increase peripheral inflammation, which also increases pain.

- Muscle cramping

- The cause of cramping is unknown, but may be related to elevated lactate, increased calcium signaling across the sarcoplasmic reticulum caused by membrane instability from reduced levels of ATP, or increased levels of free adenosine.

- Muscle weakness

- Muscle weakness is not a major symptom, though the progressive effects of chronic muscle damage from rhabdomyolysis will eventually cause significant weakness. Similarly, the long-term metabolic effects may result in nerve damage.

1) Detection of orotic acid in urine

2) Deficiency of Enzymes orotate phosphoribosyl transferase and OMP decarboxylase

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.