RESUMEN
INTRODUCTION: Congenital nephrotic syndrome is usually presented with heavy proteinuria, hypoproteinaemia, oedema and hyperlipidaemia in a child from its birth until the age of 3 months. Aetiology of the disease is mutation in the relevant gene or it develops secondary to various infections. The most common form of congenital nephrotic syndrome is caused by mutation in gene for nephrin, the most important protein of the slit diaphragm. CASE OUTLINE: We present the patient with the clinical and laboratory signs of nephrotic syndrome expressed in the first day of life. Despite the adequate and regular substitution, antiproteinuric and antithrombotic therapy, complications occurred and the patient deceased. Genetic analysis revealed homozygous mutation in gene for nephrin (614del8ins2TT). Three years later, in the patient's mother who was in the 12th week of pregnancy at that time, biopsy of chorionic villi was performed and the foetal genetic material showed heterozygosity for the same recessive mutation which meant that the foetus had the status of a carrier. To the best of our knowledge, this is the first family in Serbia in which prenatal molecular--genetic testing for the congenital nephrotic syndrome was accomplished. CONCLUSION: We wish to stress the importance of molecular diagnosis in patients with congenital nephrotic syndrome in order to perform early prenatal diagnosis in future pregnancies.