Propionic acidemia

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Propionic acidemia
Other namesHyperglycinemia with ketoacidosis and leukopenia
Propionic acid structure.svg
Propionic acid
Specialty Endocrinology   OOjs UI icon edit-ltr-progressive.svg
Symptoms Poor muscle tone, lethargy, vomiting
Diagnostic method Genetic testing; high levels of propionic acid in the urine
TreatmentLow-protein diet
Prognosis Development may be normal, or patients may have lifelong learning disabilities

Propionic acidemia, also known as propionic aciduria or propionyl-CoA carboxylase deficiency (PCC deficiency), [1] is a rare autosomal recessive metabolic disorder, classified as a branched-chain organic acidemia. [2] [3]

Contents

The disorder presents in the early neonatal period with poor feeding, vomiting, lethargy, and lack of muscle tone. [4] Without treatment, death can occur quickly, due to secondary hyperammonemia, infection, cardiomyopathy, or brain damage. [5]

Symptoms and signs

Propionic acidemia can vary in severity. [6] Severe propionic acidemia lead to symptoms already seen in newborns. [7] Symptoms include poor feeding, vomiting, dehydration, acidosis, low muscle tone (hypotonia), seizures, and lethargy. The effects of propionic acidemia quickly become life-threatening.

Long-term complications can include chronic kidney disease, [8] cardiomyopathy, and prolonged QTc interval. [9]

Pathophysiology

Propionic acidemia is caused by a defect in enzyme called propionyl-CoA carboxylase. Odd-chain FA oxydation.png
Propionic acidemia is caused by a defect in enzyme called propionyl-CoA carboxylase.
Propionic acidemia has an autosomal recessive pattern of inheritance. Autorecessive.svg
Propionic acidemia has an autosomal recessive pattern of inheritance.

In healthy individuals, enzyme propionyl-CoA carboxylase converts propionyl-CoA to methylmalonyl-CoA. This is one of many steps in the process of converting certain amino acids and fats into energy. Individuals with propionic acidemia cannot perform this conversion because the enzyme propionyl-CoA carboxylase is nonfunctional. The essential amino acids valine, methionine, isoleucine, and threonine can not be converted and this leads to a buildup of propionyl-CoA. Instead of being converted to methylmalonyl-CoA, propionyl-CoA is then converted into propionic acid, which builds up in the bloodstream. This in turn causes an accumulation of dangerous acids and toxins, which can cause damage to the organs.[ citation needed ]

In many cases, propionic acidemia can damage the brain, heart, kidney, liver, cause seizures and delays to normal development such as walking or talking. The accumulation of propionic acid is known to induce differential responses in different organs. The heart and liver are specific targets of the complication. The patient may need to be hospitalized to prevent breakdown of proteins within the body. Dietary needs must be closely managed.[ citation needed ]

Mutations in both copies of the PCCA or PCCB genes cause propionic acidemia. [10] These genes contain instructions to form alpha- and beta-subunits of PCC, the enzyme called propionyl-CoA carboxylase.

PCC is required for the normal breakdown of the essential amino acids valine, isoleucine, threonine, and methionine, as well as certain odd-chained fatty-acids. Mutations in the PCCA or PCCB genes disrupt the function of the enzyme, preventing these acids from being metabolized. As a result, propionyl-CoA, propionic acid, ketones, ammonia, and other toxic compounds accumulate in the blood, causing the signs and symptoms of propionic acidemia. Hyperammonemia develops due to the inhibitory effects of propionyl-CoA on N-acetylglutamate synthase, indirectly resulting in slowing of the urea cycle. [11]

Diagnosis

Elevated metabolites of propionic acid (for example, 3-hydroxypropionate, 2-methylcitrate, tiglylglycine, propionylglycine) found in blood and urine along with normal activity of biotinidase and normal levels of methylmalonic acid. [9]

Management

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 L-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 them 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. [12]

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

Epidemiology

Propionic acidemia is inherited in an autosomal recessive pattern and is found in about 1 in 35,000 [10] live births in the United States. The condition appears to be more common in Saudi Arabia, [13] with a frequency of about 1 in 3,000. [10] The condition also appears to be common in Amish, Mennonite and other populations with higher frequency of consanguinity. [14]

History

In 1957, a male child was born with poor mental development, repeated attacks of acidosis, and high levels of ketones and glycine in the blood. Upon dietary testing, Dr. Barton Childs discovered that his symptoms worsened when given the amino acids leucine, isoleucine, valine, methionine, and threonine. In 1961, the medical team at Johns Hopkins Hospital in Baltimore, Maryland published the case, calling the disorder ketotic hyperglycinemia. In 1969, using data from the original patient's sister, scientists established that propionic acidemia was a recessive disorder, and that propionic acidemia and methylmalonic acidemia are caused by deficiencies in the same enzyme pathway. [15]

See also

Related Research Articles

An essential amino acid, or indispensable amino acid, is an amino acid that cannot be synthesized from scratch by the organism fast enough to supply its demand, and must therefore come from the diet. Of the 21 amino acids common to all life forms, the nine amino acids humans cannot synthesize are valine, isoleucine, leucine, methionine, phenylalanine, tryptophan, threonine, histidine, and lysine.

<span class="mw-page-title-main">Methylmalonic acidemia</span> Medical condition

Methylmalonic acidemia, also called methylmalonic aciduria, is an autosomal recessive metabolic disorder that disrupts normal amino acid metabolism. It is a classical type of organic acidemia. The result of this condition is the inability to properly digest specific fats and proteins, which in turn leads to a buildup of a toxic level of methylmalonic acid in the blood.

<span class="mw-page-title-main">Hyperammonemia</span> Medical condition

Hyperammonemia is a metabolic disturbance characterised by an excess of ammonia in the blood. It is a dangerous condition that may lead to brain injury and death. It may be primary or secondary.

<span class="mw-page-title-main">Isovaleric acidemia</span> Medical condition disrupting normal metabolism

Isovaleric acidemia is a rare autosomal recessive metabolic disorder which disrupts or prevents normal metabolism of the branched-chain amino acid leucine. It is a classical type of organic acidemia.

<span class="mw-page-title-main">Maple syrup urine disease</span> Autosomal recessive metabolic disorder

Maple syrup urine disease (MSUD) is an autosomal recessive metabolic disorder affecting branched-chain amino acids. It is one type of organic acidemia. The condition gets its name from the distinctive sweet odor of affected infants' urine and earwax, particularly prior to diagnosis and during times of acute illness.

Glutaric acidemia type 1 (GA1) is an inherited disorder in which the body is unable to completely break down the amino acids lysine, hydroxylysine and tryptophan. Excessive levels of their intermediate breakdown products can accumulate and cause damage to the brain, but particularly the basal ganglia, which are regions that help regulate movement. GA1 causes secondary carnitine deficiency, as glutaric acid, like other organic acids, is detoxified by carnitine. Mental retardation may occur.

<span class="mw-page-title-main">Methylmalonyl-CoA mutase deficiency</span> Medical condition

Methylmalonyl-CoA mutase is a mitochondrial homodimer apoenzyme that focuses on the catalysis of methylmalonyl CoA to succinyl CoA. The enzyme is bound to adenosylcobalamin, a hormonal derivative of vitamin B12 in order to function. Methylmalonyl-CoA mutase deficiency is caused by genetic defect in the MUT gene responsible for encoding the enzyme. Deficiency in this enzyme accounts for 60% of the cases of methylmalonic acidemia.

<span class="mw-page-title-main">Methylmalonyl-CoA mutase</span>

Methylmalonyl-CoA mutase (EC 5.4.99.2, MCM), mitochondrial, also known as methylmalonyl-CoA isomerase, is a protein that in humans is encoded by the MUT gene. This vitamin B12-dependent enzyme catalyzes the isomerization of methylmalonyl-CoA to succinyl-CoA in humans. Mutations in MUT gene may lead to various types of methylmalonic aciduria.

<span class="mw-page-title-main">Amino acid synthesis</span> The set of biochemical processes by which amino acids are produced

Amino acid synthesis is the set of biochemical processes by which the amino acids are produced. The substrates for these processes are various compounds in the organism's diet or growth media. Not all organisms are able to synthesize all amino acids. For example, humans can synthesize 11 of the 20 standard amino acids. These 11 are called the non-essential amino acids).

Propionyl-CoA is a coenzyme A derivative of propionic acid. It is composed of a 24 total carbon chain and its production and metabolic fate depend on which organism it is present in. Several different pathways can lead to its production, such as through the catabolism of specific amino acids or the oxidation of odd-chain fatty acids. It later can be broken down by propionyl-CoA carboxylase or through the methylcitrate cycle. In different organisms, however, propionyl-CoA can be sequestered into controlled regions, to alleviate its potential toxicity through accumulation. Genetic deficiencies regarding the production and breakdown of propionyl-CoA also have great clinical and human significance.

<span class="mw-page-title-main">Propionyl-CoA carboxylase</span>

Propionyl-CoA carboxylase (EC 6.4.1.3, PCC) catalyses the carboxylation reaction of propionyl-CoA in the mitochondrial matrix. PCC has been classified both as a ligase and a lyase. The enzyme is biotin-dependent. The product of the reaction is (S)-methylmalonyl CoA.

<span class="mw-page-title-main">Methylmalonyl-CoA</span> Chemical compound

Methylmalonyl-CoA is the thioester consisting of coenzyme A linked to methylmalonic acid. It is an important intermediate in the biosynthesis of succinyl-CoA, which plays an essential role in the tricarboxylic acid cycle. The compound is sometimes referred to as "methylmalyl-CoA".

<span class="mw-page-title-main">Methylmalonyl CoA epimerase</span>

Methylmalonyl CoA epimerase is an enzyme involved in fatty acid catabolism that is encoded in human by the "MCEE" gene located on chromosome 2. It is routinely and incorrectly labeled as "methylmalonyl-CoA racemase". It is not a racemase because the CoA moiety has 5 other stereocenters.

<span class="mw-page-title-main">Hypervalinemia</span> Medical condition

Hypervalinemia is a rare autosomal recessive metabolic disorder in which urinary and serum levels of the branched-chain amino acid valine are elevated, without related elevation of the branched-chain amino acids leucine and isoleucine. It is caused by a deficiency of the enzyme valine transaminase.

Organic acidemia, 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.

<span class="mw-page-title-main">Aldehyde dehydrogenase 6 family, member A1</span> Protein-coding gene in the species Homo sapiens

Methylmalonate-semialdehyde dehydrogenase [acylating], mitochondrial (MMSDH) is an enzyme that in humans is encoded by the ALDH6A1 gene.

Tiglyl-CoA is an intermediate in the metabolism of isoleucine. It is an inhibitor of N-acetylglutamate synthetase.

Protein propionylation is a post-translational modification that is characterized by the addition of a propionyl-group to a lysine amino acid residue of a protein. Lysine propionylation was first identified on histone proteins. but was later also identified on non-histone proteins. Although the role of protein propionylation is till not completely elucidated, histone propionylation has been observed to be a mark of active chromatin. The substrate for protein propionylation is propionyl-CoA. Propionyl-CoA in the cell is metabolised by the enzyme propionyl-CoA carboxylase. In patients with propionic acidemia, a rare autosomal recessive metabolic disorder, propionyl-CoA levels elevated and increased propionylation has been observed, which might contribute to the pathology in these patients.

Combined malonic and methylmalonic aciduria (CMAMMA), also called combined malonic and methylmalonic acidemia is an inherited metabolic disease characterized by elevated levels of malonic acid and methylmalonic acid. Some researchers have hypothesized that CMAMMA might be one of the most common forms of methylmalonic acidemia, and possibly one of the most common inborn errors of metabolism. Due to being infrequently diagnosed, it most often goes undetected.

References

  1. ↑ Online Mendelian Inheritance in Man (OMIM): 606054
  2. ↑ Ravn K; Chloupkova M; Christensen E; Brandt NJ; Simonsen H; Kraus JP; Nielsen IM; Skovby F; Schwartz M (July 2000). "High incidence of propionic acidemia in greenland is due to a prevalent mutation, 1540insCCC, in the gene for the beta-subunit of propionyl CoA carboxylase". American Journal of Human Genetics. 67 (1): 203–206. doi:10.1086/302971. PMC   1287078 . PMID   10820128.
  3. ↑ Deodato F, Boenzi S, Santorelli FM, Dionisi-Vici C (2006). "Methylmalonic and propionic aciduria". Am J Med Genet C Semin Med Genet . 142 (2): 104–112. doi:10.1002/ajmg.c.30090. PMID   16602092. S2CID   21114631.
  4. ↑ "Propionic acidemia". National Center for Advancing Translational Sciences. 2 Dec 2015. Retrieved 6 June 2018.
  5. ↑ Hamilton RL, Haas RH, Nyhan WC, Powell HC, Grafe MR (1995). "Neuropathology of propionic acidemia: a report of two patients with basal ganglia lesions". Journal of Child Neurology. 10 (1): 25–30. doi:10.1177/088307389501000107. PMID   7769173. S2CID   12674920.
  6. ↑ Shchelochkov, Oleg A.; Manoli, Irini; Juneau, Paul; Sloan, Jennifer L.; Ferry, Susan; Myles, Jennifer; Schoenfeld, Megan; Pass, Alexandra; McCoy, Samantha; Van Ryzin, Carol; Wenger, Olivia; Levin, Mark; Zein, Wadih; Huryn, Laryssa; Snow, Joseph (August 2021). "Severity modeling of propionic acidemia using clinical and laboratory biomarkers". Genetics in Medicine. 23 (8): 1534–1542. doi: 10.1038/s41436-021-01173-2 . ISSN   1530-0366. PMC   8354856 . PMID   34007002. S2CID   234779025.
  7. ↑ Shchelochkov, Oleg A.; Carrillo, Nuria; Venditti, Charles (1993), Adam, Margaret P.; Everman, David B.; Mirzaa, Ghayda M.; Pagon, Roberta A. (eds.), "Propionic Acidemia", GeneReviews®, Seattle (WA): University of Washington, Seattle, PMID   22593918 , retrieved 2022-11-26
  8. ↑ Shchelochkov, Oleg A.; Manoli, Irini; Sloan, Jennifer L.; Ferry, Susan; Pass, Alexandra; Van Ryzin, Carol; Myles, Jennifer; Schoenfeld, Megan; McGuire, Peter; Rosing, Douglas R.; Levin, Mark D. (2019-06-28). "Chronic kidney disease in propionic acidemia". Genetics in Medicine. 21 (12): 2830–2835. doi:10.1038/s41436-019-0593-z. ISSN   1530-0366. PMC   7045176 . PMID   31249402.
  9. 1 2 Shchelochkov, Oleg A.; Carrillo, Nuria; Venditti, Charles (1993), Adam, Margaret P.; Ardinger, Holly H.; Pagon, Roberta A.; Wallace, Stephanie E. (eds.), "Propionic Acidemia", GeneReviews®, University of Washington, Seattle, PMID   22593918 , retrieved 2019-09-29
  10. 1 2 3 http://mayoresearch.mayo.edu/mayo/research/barry_lab/ropionic-Aciademia.cfm Archived 2008-08-29 at the Wayback Machine
    Barry Lab - Vector and Virus Engineering. Gene therapy for Propionic Acidemia
  11. ↑ Dercksen, M.; IJlst, L.; Duran, M.; Mienie, L. J.; van Cruchten, A.; van der Westhuizen, F. H.; Wanders, R. J. A. (December 2014). "Inhibition of N-acetylglutamate synthase by various monocarboxylic and dicarboxylic short-chain coenzyme A esters and the production of alternative glutamate esters". Biochimica et Biophysica Acta (BBA) - Molecular Basis of Disease. 1842 (12 Pt A): 2510–2516. doi: 10.1016/j.bbadis.2013.04.027 . ISSN   0006-3002. PMID   23643712.
  12. ↑ Saudubray JM, Van Der Bergh G, Walter J : Inborn Metabolic Diseases Diagnosis and Treatment (2012)
  13. ↑ Al-Odaib AN, Abu-Amaro KK, Ozand PT, Al-Hellani AM (2003). "A new era for preventive genetic programs in the Arabian Peninsula". Saudi Medical Journal. 24 (11): 1168–1175. PMID   14647548.
  14. ↑ Kidd JR, Wolf B, Hsia E, Kidd KK (1980). "Genetics of propionic acidemia in a Mennonite-Amish kindred". Am J Hum Genet. 32 (2): 236–245. PMC   1686010 . PMID   7386459.
  15. ↑ Hsia, T. (2003). "How Ketotic Hyperglycinemia Became Propionic Acidemia" (PDF). Paresearch.org. Retrieved 7 June 2018.
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