[Duplication of the X-chromosomal Xq28 region containing the MECP2 gene in X-linked intellectual disability syndrome Lubs-type].

In the case of a suspected genetic disease, it is a big challenge to integrate the wide range of symptoms, to select the appropriate diagnostic steps and then to evaluate the results. In this case report, we present the medical history of a boy with congenital heart defects, neurodevelopmental and endocrine disorders. In connection with recurrent, psychomotor developmental delay, detection of minor anomalies and recurrent, severe sepsis since his birth, we started his genetic testing. Multiplex ligation-dependent probe amplification (MLPA-) analysis identified MECP2 duplication syndrome. This genetic syndrome, also called X-linked intellectual disability syndrome Lubs-type, is an X-linked recessive genetic defect. The exact frequency of this genetic disorder is unknown. We know about 200 people in the world, based on literature data. The severity of the clinical symptoms is related to the size of the duplicated chromosome segment. In our patient the affected region, in addition to MECP2, also contained SLC6A8, IDH3G, L1CAM, IRAK1, FLNA, GDI1, DKC1, F8 and VAMP7 genes. These genes may have contributed to the appearance of the diverse clinical picture. We emphasize the pathological role of the reduced cortisol response in the background of recurrent, severe septic conditions. A wide spectrum of genetic testing methods is available, but it depends on the clinician to initiate them. Our main goal with this announcement is to draw attention to these special analyses, which can shorten the diagnostic path, therefore during the next pregnancis the prenatal genetic diagnosis is possible. Orv Hetil. 2025; 166(8): 313–316.