الفهرس 
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Abstract
Inborn error of metabolism (IEM) refers to a disorder in which single gene defects cause clinically significant blocks in metabolic pathways (Thomas JA et al., 2011).IEM results from mutations in DNA that code for a specific protein, which may act as an enzyme, receptor, transport vehicle, membrane pump or structural element (Kulkarni ML et al., 2009).
Most IEM are inherited as autosomal recessive trait and neonates with parental consanguinity are at increased risk (Rezvani I. et al., 2007).
The prevalence of IEM is determined by the geographical and ethnic composition of the population. For example, among live births, the estimated prevalence are 1 in 1,400 to 1 in 5,000 in the United States (Gupta A. et al 2007), 1 in 2,800 in South Korea (Yoon HR, et al 2005), 1 in 784 in the United Kingdom (Sanderson S, et al 2006) , With the ever-increasing rate at which new ones and variations of old ones are being recognized, IEM is an area of paediatrics that is assuming an increasing role in both private practice and tertiary hospitals referral (Tasker RC et al 2008).
There are four groups of clinical circumstances in which physicians are faced with the possibility of a metabolic disorder:
a) Early symptoms in the antenatal and neonatal period.
b) Later onset acute (and recurrent) attacks of symptoms such as coma, ataxia, vomiting, acidosis, exercise intolerance,cardiac, renal, liver or other organ failure.
c) chronic and progressive neurological symptoms (developmental delay, mental retardation, epilepsy, neurological deterioration and psychiatric signs).
d) Specific and permanent organ/system presentations that may concern all medical specialities (cardiology, dermatology, endocrinology, gastroenterology, haematology, etc.).
The first step is baseline investigations which are applied for all sick neonates . Measurement of blood gas and calculation of the anion gap gives invaluable information and direct the investigations according to the differential diagnosis. Metabolic acidosis with normal anion gap (Fitzpatrick, 2006 and Levy, 2009a) indicates that the patient looses bicarbonate through either the kidney or the gut. Increased anion gap shows that acid accumulates. Acid could be lactic acid like in mitochondrial disorders, organic acid as in organic aciduria, or ketoacids as in ketolytic defects and organic acidurias(Dagli et al., 2008 and Nitu et al., 2011).
Measurement of amino acids, acylcarnitine profile and organic acids provides an insight to the metabolism and disorders of fatty acid oxidation, organic aciduria and aminoacidopathy. The third line investigations are specific, confirmatory, and occasionally highly specialized that need to be mostly guided by a pediatrician with some experience in dealing with IEM.
Newborn screening is a vital process that identifies apparently healthy infants with serious inherited disorders, generally metabolic in origin, that are usually correctable by dietary or drug interventions before they suffer significant morbidity or mortality(Abhyankar et al., 2010). Carlson commented that, “newborn screening represents one of the major child health advances of this past century” (Carlson, 2004).In expanded newborn screening, a single test allows for early detection and treatment of a large number of disorders and it can potentially prevent serious consequences(Waisbren, 2008 and Wilcken, 2010).
Aims of treatment of inborn errors of metabolism are:
1. To reduce the formation of toxic metabolites by decreasing substrate availability (by stopping feeds and preventing endogenous catabolism).
2. To provide adequate calories.
3. To enhance the excretion of toxic metabolites.
4. To institute co-factor therapy for specific disease and also empirically if diagnosis not established.
5. Supportive care- treatment of seizures (avoid sodium valproate – may increase ammonia levels), maintain euglycemia and normothermia, fluid, electrolyte & acid-base balance, treatment of infection, mechanical ventilation if required.
Recommendation
Take good history .
Postpartum autopathy .
Advice obligatory to eradicate this problem.