Organic acidurias in Egyptian children: The urge for high-risk screening.

BACKGROUND: Organic acidurias are a group of inborn errors of metabolism. They present a significant diagnostic challenge and are associated with serious morbidity and mortality. They are considered the most frequent inborn errors of metabolism among high-risk children. Gas chromatography-mass spectrometry is a reliable diagnostic technique for organic acidurias. This hospital-based study aimed to quantify the frequency of organic acidurias among a group of high-risk Egyptian pediatric patients and to highlight the importance of high-risk screening for such disorders. METHODS: One hundred and fifty high-risk children who presented to the inherited metabolic disease unit and the pediatric intensive care units of Cairo University Children Hospital were tested for urine organic acids using gas chromatography-mass spectrometry. RESULTS: Thirty percent (45/150) of the patients were confirmed as having an altered organic acids profile. Neurological manifestations were the most common presentation. Glutaric aciduria type I and maple-syrup urine disease were the most common disorders encountered among the group that was studied. CONCLUSION: Organic acid detection by gas chromatography-mass spectrometry is key to the diagnosis of many metabolic disorders. Until a national expanded newborn screening program is established, high-risk screening is strongly encouraged for the early detection of, and proper intervention for such disorders among Egyptian children.

Novel biomarkers for lysosomal storage disorders: Metabolomic and proteomic approaches.

Lysosomal storage disorders (LSDs) are characterized by the accumulation of specific disease substrates inside the lysosomes of various cells, eventually leading to the deterioration of cellular function and multisystem organ damage. With the continuous discovery and validation of novel and advanced therapies for most LSDs, there is an urgent need to discover more versatile and clinically relevant biomarkers. The utility of these biomarkers should ideally extend beyond the screening and diagnosis of LSDs to the evaluation of disease severity and monitoring of therapy. Metabolomic and proteomic approaches provide the means to the discovery and validation of such novel biomarkers. This is achieved mainly through the application of various mass spectrometric techniques to common and easily accessible biological samples, such as plasma, urine and dried blood spots. In this review, we tried to summarize the complexity of the lysosomal disorders phenotypes, their current diagnostic and therapeutic approaches, the various techniques supporting metabolomic and proteomic studies and finally we tried to explore the newly discovered biomarkers for most LSDs and their reported clinical values.