Abstract
Introduction: Inborn Errors of Metabolism (IEM) represent a group of >1000 rare genetic disorders that are caused by a defect of single/multiple enzymes or changes in structural, assembling and transporting proteins that participate in metabolic pathways. Since any system can be affected, variable clinical symptoms may occur, leading to a diagnostic delay.
Aim: To provide clear overview of the main key clinical and laboratory findings of IEM encountered by both primary health care or hospital physicians - pediatricians. Results: Main clinical features of IEM are represented by developmental regression, pharmacoresistant epilepsy, cardiomyopathy, myopathic syndrome or muscle pain in rhabdomyolysis and hepato-/splenomegaly.
As much as 70% of a childhood urolithiasis are caused by one of the IEM. Detailed ophthalmic examination may reveal corneal clouding or cataract, ophthalmoplegia, pigmentary retinopathy and optic neuropathy.
Some of the symptoms may be helpful in making the right diagnosis faster at a glance, such as craniofacial dysmorphism, hypertrichosis, atypical structure of adnexa and some bone changes. The main laboratory abnormalities include hypoglycemia, hyperammonemia, dyslipidemia and (cholestatic) hepatopathy.
Standardized cerebrospinal fluid examination is crucial for the diagnosis of some of the IEM that can be potentially treatable. Conclusion: Although individual IEM are considered rare, their estimated total prevalence is higher than 1:200.
It is therefore very likely, that most physicians will experience at least one of the IEM in their lifetime. Setting up the correct diagnosis is of utmost importance for initiating therapy as for genetic and prenatal counselling.