Methylmalonic Aciduria due to Methylmalonyl-CoA Mutase Deficiency

Alternative Names

  • Methylmalonic Acidemia due to Methylmalonyl-CoA Mutase Deficiency
  • MMA due to MCM Deficiency
  • Methylmalonic Aciduria, mut Type
  • Methylmalonic Aciduria, mut(0) Type
  • Methylmalonic Aciduria, mut(-) Type
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WHO-ICD-10 version:2010

Endocrine, nutritional and metabolic diseases

Metabolic disorders

OMIM Number

251000

Mode of Inheritance

Autosomal recessive

Gene Map Locus

6p12.3

Description

Methylmalonic Acidemia (MMA) is a metabolic disorder of methylmalonate and cobalamin metabolism. The signs and symptoms of this condition develop in early infancy. Infants present with vomiting, hypotonia, dehydration, lethargy, seizures, and failure to thrive. MMA is suspected in neonates with progressive encephalopathy along with severe metabolic acidosis, ketosis and ketonuria, hyperammonemia, hyperglycinemia, thrombocytopenia, and neutropenia.

Defects or absence of the Methylmalonyl-CoA Mutase (MCM) enzyme is the underlying cause in more than half of MMA cases. Mutations in MUT gene, which encodes MCM can lead to either complete enzyme deficiency [mut(0)], or partial enzyme deficiency [mut(-)].  

Epidemiology in the Arab World

View Map
Subject IDCountrySexFamily HistoryParental ConsanguinityHPO TermsVariantZygosityMode of InheritanceReferenceRemarks
251000.1United Arab EmiratesUnknown Methylmalonic aciduriaNM_000255.4:c.1420C>THomozygousAutosomal, RecessiveAl-Jasmi at al. 2016 Mutation identified ...
251000.2United Arab EmiratesUnknown Methylmalonic aciduriaNM_000255.4:c.2080C>THomozygousAutosomal, RecessiveAl-Jasmi at al. 2016 Mutation identified ...

Other Reports

Bahrain

Al-Arrayed (Personal communication, Dubai, 2006) indicated that 3-methylglutaric acidemia occurs in Bahrain at an approximate incidence of 6/10,000 births.

Lebanon

In a retrospective analysis of IEMs diagnosed over a 12-year period (1998-2010) in a hospital in Lebanon, Karam et al. (2013) found 23 patients diagnosed with methylmalonic aciduria. Five of these were through newborn screening. Mean age at diagnosis was of 1 year and 5-months.

Morocco

Prada et al (2011) described a male patient with urine organic acids who was diagnosed with MMA type Mutase0. The child was born to consanguineous parents, and died in infancy

Oman

Joshi et al. (2002) carried out a retrospective analysis of all patients born with inborn errors of metabolism in Oman between June 1998 and December 2000. Among the 82 patients, one was diagnosed with methylmalonic aciduria [CTGA Database Editor's note: Computed annual incidence rate is 0.8/100,000]. Few years later, Joshi and Venugopalan (2007) conducted a study over a seven year period (1998-2005) to evaluate the clinical profiles of 166 neonates at high risk of having inborn errors of metabolism using Tandem Mass Spectrometry (TMS). Out of a total of 38 neonates with positive TMS results, one baby, aged six days, was diagnosed with Methylmalonic Acidemia. He was born to consanguineous parents and presented with acute neonatal encephalopathy.

Al-Riyami et al (2012) reported on the types and patterns of IEMs encountered in a sample of 1100 high-risk neonates referred to SQU Hospital in Oman over a 10-year period (1998-2002). MS/MS was used to analyze blood samples from heel pricks. A total of 119 of these neonates were found to test positive for an IEM. MMA was detected in five neonates (three males, two females), belonging to two families. Four of the patients had a family history of the condition, while three had consanguineous parents.

Qatar

In 2003, the Hamad Medical Corporation, in partnership with the University Children's Hospital of Heidelberg built a comprehensive newborn screening program. Between December 2003 and July 2006, Lindner et al. (2007) investigated 25,214 neonates born in Qatar for inborn errors of metabolism and endocrine disorders. One neonate was diagnosed with MMA deficiency. The NBS result was available at 8-days of age, and treatment was started immediately.

Saudi Arabia

Brismar and Ozand (1994) reported the results of CT and/or MRI of the brain in 107 patients with different types of organic acidemia. The CSF spaces were wide in more than two-thirds of the patients, in 46 slightly-to-moderately and in 26 markedly-to-severely dilated. Marked widening of the opercula was found in all 5 patients with glutaric acidemia type 1, but open opercula was also found in other organic acidemias. White matter changes were found in about half the patients, in 28 mildly-to-moderately pronounced, in another 28 marked or severe. Basal ganglia or central pathway pathology was seen in a total of 34 patients. These changes in 25 patients involved the caudate and/or lentiform nuclei: in 14 cases the T2 signal was increased and volume loss was present, in 9 cases increased T2 signal with preserved volume was found (in one of these the changes were transient). In 2 patients, both with ethylmalonic aciduria (cause unknown), only small high T2 spots were seen in the caudate heads and the putamina. In 4 patients, all suffering from methylmalonic acidemia, only the globus pallidus was affected.

Worthen et al. (1994) retrospectively analyzed 144 patients who were followed for 1-5 years for the severity and frequency of hypoglycemia. The patients were mainly Saudi; however, 10-25% were from neighboring countries in the Arabian peninsula. Less than 50% of the patients with MSUD older than 8 months, pyruvate carboxylase deficiency, methylmalonic acidemia, or propionic acidemia had hypoglycemia during metabolic crisis.

Moammar et al. (2010) reviewed all patients diagnosed with inborn errors of metabolism (IEM) from 1983 to 2008 at Saudi Aramco medical facilities in the Eastern province of Saudi Arabia. During the study period, 165530 Saudi infants were born, of whom a total of 248 newborns were diagnosed with 55 IEM. Affected patients were evaluated based on clinical manifestations or family history of similar illness and/or unexplained neonatal deaths. Almost all patients were born to consanguineous parents. Organic acidopathies (OA) were diagnosed in 48 out of 248 cases (19%), which constituted the second largest group of IEM found in this cohort after lysosomal storage disease. Among OA patients, two cases from two families were found to have methylmalonic acidemia due to mutase deficiency. The estimated incidence of this condition is 1 in 100,000 live births.   Methylmalonic acidemia accounts for 27% of all cases of OA found in this cohort. The authors concluded that data obtained from this study underestimate the true figures of various IEM in the region. Therefore, there is an urgent need for centralized newborn screening program that utilizes tandem mass spectrometry, and offers genetic counseling for these families.

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