Detection of the disorder is possible with an organic acid analysis of the urine. Patients with SSADH deficiency will excrete high levels of GHB but this can be difficult to measure since GHB has high volatility and may be obscured on gas chromatography or mass spectrometry studies by a high urea peak. Other GABA metabolites can also be identified in urine such as glycine. Finally, succinic semialdehyde dehydrogenase levels can be measured in cultured leukocytes of the patient. This occurs due to the accumulation of 4,5-dihydroxyhexanoic acid which is normally undetectable in mammalian tissues but is characteristic of SSADH deficiency. This agent can eventually compromise the pathways of fatty acid, glycine, and pyruvate metabolism, and then become detectable in patients' leukocytes. Such enzyme levels can also be compared to non-affected parents and siblings.

Cranial computed topography, magnetic resonance imaging, and flurodeoxyglucose positron emission topography are just some of the neuroimaging modalities that have been used to diagnose patients with SSADH deficiency. On the basis of 29 previously published cases that had imaging results available, there were some common abnormalities found. These included increased T2-weighted signal abnormalities involving the globus pallidi bilaterally and symmetrically as well as the presence of subcortical white matter. Similar abnormalities have been identified in the brainstem and cerebellar dentate nucleus.

Signal intensity on a T2 image may be a result of edema or an inflammatory response. Because this type of imaging is a water detecting sequence, any form of calcification or mineralization would also appear dark, thus explaining why accumulation of extra blood or fluid would appear bright on a T2 image. Another explanation for signal intensity may be demyelination since the globus pallidi are traversed by a number of myelinated axons, thus confirming Ren and Mody’s 2003 work proving that repeated exposure of GHB to MAP kinase affected myelin expression, thus causing the numerous neurological dysfunctions seen in SSADH deficiency patients. Ultimately, because the globus pallidus is intimately linked with the basal ganglia and thalamus, it would be expected that some of the motor dysfunctions seen in SSADH patients such as ataxia and hyporeflexia would be common.

Human findings provide insufficient data for developing treatments due to differences in the patients physiological and metabolic disorders thus, a suitable alternative animal model is essential in obtaining a better understanding of the SR deficiency. In this particular case, researchers used silkworms to identify and characterize mutations relating to SPR activity from an initial purified state created in the larvae of the silkworm. The researchers used genetic and biochemical approaches to demonstrate oral administration of BH and dopamine which increased the survival rates of the silkworm larvae. The results indicate that BH deficiency in silkworms leads to death in response to the lack of dopamine. This shows that silkworms can be useful insect models in additional SR deficiency research and study.

The diagnosis of SR deficiency is based on the analysis of the pterins and biogenic amines found in the cerebrospinal fluid (CSF) of the brain. The pterin compound functions as a cofactor in enzyme catalysis and biogenic amines which include adrenaline, dopamine, and serotonin have functions that vary from the control of homeostasis to the management of cognitive tasks. This analysis reveals decreased concentrations of homovanillic acid (HVA), 5-hydroxyindolacetic acid (HIAA), and elevated levels of 7,8-dihydrobiopterin, a compound produced in the synthesis of neurotransmitters. Sepiapterin is not detected by the regularly used methods applied in the investigation of biogenic monoamines metabolites in the cerebrospinal fluid. It must be determined by specialized methods that work by indicating a marked and abnormal increase of sepiapterin in cerebrospinal fluid. Confirmation of the diagnosis occurs by demonstrating high levels of CSF sepiapterin and a marked decrease of SR activity of the fibroblasts along with SPR gene molecular analysis.

A 2006 study of 279 patients found that of those with symptoms (185, 66%), 95% had suffered an encephalopathic crises usually with following brain damage. Of the persons in the study, 49 children died and the median age of death was 6.6 years. A Kaplan-Meier analysis of the data estimated that about 50% of symptomatic cases would die by the age of 25.

Stress caused by infection, fever or other demands on the body may lead to worsening of the signs and symptoms, with only partial recovery.

Infant mortality is high for patients diagnosed with early onset; mortality can occur within less than 2 months, while children diagnosed with late-onset syndrome seem to have higher rates of survival. Patients suffering from a complete lesion of mut0 have not only the poorest outcome of those suffering from methylaonyl-CoA mutase deficiency, but also of all individuals suffering from any form of methylmalonic acidemia.

Diagnostic methods

Diagnosis is based mainly on clinical findings and laboratory test results. Plasma concentrations of ammonia (>150 µmol/L) and citrulline (200-300 µmol/L) are elevated. Elevated levels of argininosuccinic acid (5-110 µmol/L) in the plasma or urine are diagnostic. Molecular genetic testing confirms diagnosis. Newborn screening for ASA is available in the U.S. and parts of Australia, and is considered in several European countries<

The treatment of 2-Hydroxyglutaric aciduria is based on seizure control, the prognosis depends on how severe the condition is.

Clinically, MCADD or another fatty acid oxidation disorder is suspected in individuals who present with lethargy, seizures, coma and hypoketotic hypoglycemia, particularly if triggered by a minor illness. MCADD can also present with acute liver disease and hepatomegaly, which can lead to a misdiagnosis of Reye syndrome. In some individuals, the only manifestation of MCADD is sudden, unexplained death often preceded by a minor illness that would not usually be fatal.

In areas with expanded newborn screening using tandem mass spectrometry (MS/MS), MCADD is usually detected shortly after birth, by the analysis of blood spots collected on filter paper. Acylcarnitine profiles with MS/MS will show a very characteristic pattern of elevated hexanoylcarnitine (C6), octanoylcarnitine (C8), decanoylcarnitine (C10) or decenoylcarnitine (C10:1), with C8 being greater than C6 and C10. Secondary carnitine deficiency is sometimes seen with MCADD, and in these cases, acylcarnitine profiles may not be informative. Urine organic acid analysis by gas chromatography-mass spectrometry (GC-MS) will show a pattern of dicarboxylic aciduria with low levels of ketones. Traces of acylglycine species may also be detected. Asymptomatic individuals may have normal biochemical lab results. For these individuals, targeted analysis of acylglycine species by GC-MS, specifically hexanoylglycine and suberylglycine can be diagnostic. After biochemical suspicion of MCADD, molecular genetic analysis of "ACADM" can be used to confirm the diagnosis. The analysis of MCAD activity in cultured fibroblasts can also be used for diagnosis.

In cases of sudden death where the preceding illness would not usually have been fatal, MCADD is often suspected. The autopsy will often show fatty deposits in the liver. In cases where MCADD is suspected, acylcarnitine analysis of bile and blood can be undertaken postmortem for diagnosis. Where samples are not available, residual blood from newborn screening may be helpful. Biochemical testing of asymptomatic siblings and parents may also be informative. MCADD and other fatty acid oxidation disorders have been recognized in recent years as undiagnosed causes of sudden infant death syndrome.

Due to the rarity of the disease, it is hard to estimate mortality rates or life expectancy. One 2003 study which followed 88 cases receiving two different kinds of treatment found that very few persons lived beyond age 20 and none beyond age 30.

One of, if not the most common form of organic acidemia, methylmalonic acidemia is not apparent at birth as symptoms usually do not present themselves until proteins are added to the infant's diet. Because of this, symptoms typically manifest anytime within the first year of life. Due to the severity and rapidity in which this disorder can cause complications when left undiagnosed, screening for methylmalonic acidemia is often included in the newborn screening exam.

Because of the inability to properly break down amino acids completely, the byproduct of protein digestion, the compound methylmalonic acid, is found in a disproportionate concentration in the blood and urine of those afflicted. These abnormal levels are used as the main diagnostic criteria for diagnosing the disorder. This disorder is typically determined through the use of a urine analysis or blood panel. The presence of methylmalonic acidemia can also be suspected through the use of a CT or MRI scan or ammonia test, however these tests are by no means specific and require clinical and metabolic/correlation. Elevated levels of ammonia, glycine, and ketone bodies may also be present in the blood and urine.

Several tests can be done to discover the dysfunction of methylmalonyl-CoA mutase. Ammonia test, blood count, CT scan, MRI scan, electrolyte levels, genetic testing, methylmalonic acid blood test, and blood plasma amino acid tests all can be conducted to determine deficiency.

There is no treatment for complete lesion of the mut0 gene, though several treatments can help those with slight genetic dysfunction. Liver and kidney transplants, and a low-protein diet all help regulate the effects of the diseases.

Less than 20 patients with MGA type I have been reported in the literature (Mol Genet Metab. 2011 Nov;104(3):410-3. Epub 2011 Jul 26.)

As of 1993 only approximately 30 people with AHC had been described in scientific literature. Due to the rarity and complexity of AHC, it is not unusual for the initial diagnosis to be incorrect, or for diagnosis to be delayed for several months after the initial symptoms become apparent. The average age of diagnosis is just over 36 months. Diagnosis of AHC is not only difficult because of its rarity, but because there is no diagnostic test, making this a diagnosis of exclusion. There are several generally accepted criteria which define this disorder, however other conditions with a similar presentation, such as HSV encephalitis, must first be ruled out. Due to these diagnostic difficulties, it is possible that the commonness of the disease is underestimated.

The following descriptions are commonly used in the diagnosis of AHC. The initial four criteria for classifying AHC were that it begins before 18 months of age, includes attacks of both hemiplegia on either side of the body, as well as other autonomic problems such as involuntary eye movement (episodic monocular nystagmus), improper eye alignment, choreoathetosis, and sustained muscle contractions (dystonia). Finally, patients suffer from intellectual disabilities, delayed development, and other neurological abnormalities. These diagnostic criteria were updated in 1993 to include the fact that all of these symptoms dissipate immediately upon sleeping. Diagnostic criteria were also expanded to include episodes of bilateral hemiplegia which shifted from one side of the body to the other.

Recent criteria have been proposed for screening for AHC early, in order to improve the diagnostic timeline. These screening criteria include focal or unilateral paroxysmal dystonia in the first 6 months of life, as well as the possibility of flaccid hemiplegia either with or separate from these symptoms. Paroxysmal ocular movements should also be considered, and these should include both binocular and monocular symptoms which show in the first 3 months of life.

Methylmalonic acidemia has varying diagnoses, treatment requirements and prognoses, which are determined by the specific genetic mutation causing the inherited form of the disorder. The following are the known genotypes responsible for methylmalonic acidemia:

The mut type can further be divided in mut0 and mut- subtypes, with mut0 characterized by a complete lack of methylmalonyl CoA mutase and more severe symptoms and mut- characterized by a decreased amount of mutase activity.

Mut-, cblB, and cblA versions of methylmalonic acidemia have been found to be cobalamin responsive. Mut0 is a nonresponsive variant.

There is a deficiency of malate in patients because fumarase enzyme can't convert fumarate into it therefore treatment is with oral malic acid which will allow the krebs cycle to continue, and eventually make ATP.

A 1994 study of the entire population of New South Wales (Australia) found 20 patients. Of these, 5 (25%) had died at or before 30 months of age. Of the survivors, 1 (5%) was severely disabled and the remainder had either suffered mild disability or were making normal progress in school. A 2006 Dutch study followed 155 cases and found that 27 individuals (17%) had died at an early age. Of the survivors, 24 (19%) suffered from some degree of disability, of which most were mild. All the 18 patients diagnosed neonatally were alive at the time of the follow-up.

Overall outcomes for AHC are generally poor, which is contributed to by AHC's various diagnostic and management challenges. In the long term, AHC is debilitating due to both the hemiplegic attacks and permanent damage associated with AHC. This damage can include cognitive impairment, behavioral and psychiatric disorders, and various motor impairments. There is, however, not yet any conclusive evidence that AHC is fatal or that it shortens life expectancy, but the relatively recent discovery of the disorder makes large data for this type of information unavailable. Treatment for AHC has not been extremely successful, and there is no cure. There are several drugs available for treatment, as well as management strategies for preventing and dealing with hemiplegic attacks.

1) Detection of orotic acid in urine

2) Deficiency of Enzymes orotate phosphoribosyl transferase and OMP decarboxylase

Patients with propionic acidemia should be started as early as possible on a low protein diet. In addition to a protein mixture that is devoid of methionine, threonine, valine, and isoleucine, the patient should also receive -carnitine treatment and should be given antibiotics 10 days per month in order to remove the intestinal propiogenic flora. The patient should have diet protocols prepared for him with a “well day diet” with low protein content, a “half emergency diet” containing half of the protein requirements, and an “emergency diet” with no protein content. These patients are under the risk of severe hyperammonemia during infections that can lead to comatose states.

Liver transplant is gaining a role in the management of these patients, with small series showing improved quality of life.

This condition is sometimes mistaken for Reye syndrome, a severe disorder that develops in children while they appear to be recovering from viral infections such as chicken pox or flu. Most cases of Reye syndrome are associated with the use of aspirin during these viral infections.

Hematological, biochemical and metabolic investigations on blood and urine between attacks are normal, as are karyotyping and EKG recordings. EKG recordings during attacks show sinus tachycardia. CT, MRI, EMG and nerve conduction studies produce normal results. EEG recordings are normal between attacks but show early-onset tachycardia during attacks. On the Neuropathic Pain Questionnaire patients indicated that pain during attacks is extremely unpleasant and typically felt deep, though also superficial on occasion. Aside from presentation of typical symptoms (see Signs and symptoms above) mutation of the gene "SCN9A" aids in appropriate diagnosis as this gene is mutated in 8 of 14 studied families.

2-hydroxyglutaric aciduria is a rare neurometabolic disorder characterized by the significantly elevated levels of hydroxyglutaric acid in ones urine. It is either autosomal recessive or autosomal dominant.

Since the early 2000s, genetic testing that measures the size of the D4Z4 deletions on 4q35 has become the preferred mechanism for confirming the presence of FSHD. As of 2007, this test is considered highly accurate but is still performed by a limited set of labs in the US, such as Athena diagnostics under test code 405. However, because the test is expensive, patients and doctors may still rely on one or more of the following tests, all of which are far less accurate and specific than the genetic test:

- Creatine kinase (CK) level: This test measures the Creatine kinase enzyme in the blood. Elevated levels of CK are related to muscle atrophy.

- electromyogram (EMG): This test measures the electrical activity in the muscle

- nerve conduction velocity (NCV): This test measures the how fast signals travel from one part of a nerve to another. The nerve signals are measured with surface electrodes (similar to those used for an electrocardiogram), and the test is only slightly uncomfortable.

- muscle biopsy: Through outpatient surgery a small piece of muscle is removed (usually from the arm or leg) and evaluated with a variety of biochemical tests. Researchers are attempting to match results of muscle biopsies with DNA tests to better understand how variations in the genome present themselves in tissue anomalies.