Disorders of organic acid (OA) metabolism are generally detected by qualitative analysis of urine organic acids by gas chromatography/mass spectrometry (GC/MS) which was well established in developed countries since 1980s. Confirmation of the diagnosis of organic acid disorders by OA analysis, enzyme analysis and molecular study is a difficult task in developing countries.
During 2001-2004, we had analysed 442 urine samples in 365 patients and identified 12 cases of organic acid disorders.
We identified the following disorders: alkaptonuria (ALK)=1, isovaleric acidemia (IVA)=3, propionic acidemia (PA)=2, methylmalonic acidemia (MMA)=3, glutaric aciduria, type I (GA-I)=1, multiple carboxylase deficiency (MCD)=1, and glutaric acidemia, type II (GA-II)=1.
OA disorders had never been diagnosed in Thailand before, until GC/MS technology was introduced to Thailand in 2001. Urine OA analysis also provided a diagnostic clue to other inborn errors of metabolism including amino acid disorders, urea cycle disorders, disorders of carbohydrate metabolism, and mitochondrial fatty acid oxidation disorders. Since then, we were able to diagnose numerous disorders, which led to prompt treatment and better outcome in our patients.
"Please cite this article as: Karam PE, et al, Diagnostic challenges of aminoacidopathies and organic acidemias in a developing country: A twelveyear experience, Clin Biochem (2013), http://dx.doi.org/10.1016/j.clinbiochem.2013.08.009 that from Kuwait (4.4%) . Reported yields for urine organic acid chromatography from other countries ranged from 2.4% in Japan  to 8% in Thailand  with intermediate values in Brazil (3.2%)  which is comparable to ours (3.9%) and slightly higher in Asia (5.6%) . "
[Show abstract][Hide abstract] ABSTRACT: Diagnosis of aminoacidopathies and organic acidemias constitute a real challenge in a developing country with high consanguinity rate and no systematic newborn screening. We report a twelve-year experience with the identification of these disorders in Lebanon, based on their clinical and biochemical profiles.
In this retrospective study, we reviewed clinical presentation and biochemical investigations of 294 patients. Traditional chromatographic methods were used for analyses. Findings were linked to the identified disorders.
Out of 2921 patients, presenting to our metabolic program with neurological, digestive, family history and/or other symptoms suggestive of aminoacidopathy or organic acidemia, 294 patients were included with confirmed amino or organic acid disorder. The overall analytical yield was 10%. Aminoacidopathies were three-fold higher than organic acidemias. Phenylketonuria and methylmalonic acidemia were the most frequent. The majority of patients (79%) were symptomatic (median age: 14months, range: 1day-44years), mainly with neurological manifestations (87%). Intellectual disability was mostly due to phenylketonuria (73%). Chronic liver failure was frequent in maple syrup urine disease (53%). Plasma amino and urine organic acid chromatography were diagnostic in 8.8% and 3.9% of analyzed cases, respectively. Change in chromatographic technique from reversed-phase to ion-exchange enhanced the detection of many aminoacidopathies.
In the absence of newborn screening, the majority of aminoacidopathy and organic acidemia cases are still diagnosed clinically. This study emphasizes the importance of clinical awareness and accurate biochemical analyses as key tools for diagnosis in countries like ours, and the necessity for a comprehensive national newborn screening program.
[Show abstract][Hide abstract] ABSTRACT: The gas chromatography/mass spectrometry (GC/MS) method for organic acid analysis was established in developed countries since 1980s, but due to the small number of experienced clinical biochemists in this field and also the short availability of mass spectrometers scarce reports exist on the prevalence of organic acidemias (OAs) in developing countries like Brazil.
During January 1994 to July 2008, we analyzed organic acids by GC/MS in urine specimens obtained from Brazilian children with clinical suspicion of metabolic diseases.
Two hundred and thirty four cases of disorders of organic acid metabolism, including 218 OAs (3.17%), were diagnosed among 6866 patients investigated. The most frequent disorders were primary lactic acidemia (57), methylmalonic acidemia (34), glutaric acidemia type I (33), propionic acidemia (18), 3-hydroxy-3-methylglutaric aciduria (17), L-2-hydroxyglutaric aciduria (9) and multiple carboxylase deficiency (9). Fourteen cases of mitochondrial fatty acid oxidation disorders, as well as 12 aminoacidopathies and 4 cases of vitamin B12 deficiency were also detected. Prompt treatment following diagnosis led to a better outcome in a considerable number of patients.
Detection of OAs in loco in developing countries is important despite the implied extra costs, since it allows rapid therapy in many cases with a significant reduction of morbidity and mortality and makes the physicians more aware of these pathologies.
Clinica chimica acta; international journal of clinical chemistry 12/2008; 400(1-2):77-81. DOI:10.1016/j.cca.2008.10.007 · 2.82 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The study of inherited metabolic disorders (IMD) in Thailand is in its infancy when compare with developed countries. Prior to 1987, majority of these disorders were clinically diagnosed since there were only a handful of clinicians and scientists with expertise in inborn errors of metabolism, lack of well-equipped laboratory facilities and government support. In developing countries, inherited metabolic disorders are not considered a priority due to the prevalence of infectious diseases such as HIV infection and congenital infections. A multicentre survey conducted in 1994 and 2001 revealed the existence of numerous cases of IMD from all over the country. Case reports and publications on IMD in Thai (and international) medical journals in past 20 years had undoubtedly raised its awareness among Thai paediatricians and scientists. In 2001, the Genetic Metabolic Centre was first established in Siriraj Hospital Faculty of Medicine, Thailand. Numerous new cases of IMD had been identified since then.
Annals of the Academy of Medicine, Singapore 12/2008; 37(12 Suppl):117-3. · 1.15 Impact Factor
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