Progress in cytogenetic methods elucidated etiology of 10% mental retardation, microcephaly with multiple anomalies due to detection of subtelomeric rearrangements. The authors report a boy, who was investigated since infancy because of clinical symptoms of Marden-Walker syndrome - severe microcephaly, seizures, blepharophimosis, stenosis of lacrimal ducts, cleft palatě, hypospadia, adductal contractures of hips and knees. Only at the age of 10 years, when multiprobe FISH method was introduced to specify genetic prognosis of reproduction for his healthy brothers, the authors were able to identify the subtelomeric deletion of chromosome 8 and telomeric trisomy of chromosome 16 - deletion in subtelomeric area 8p and trisomy in telomeric area 16p, which occurs due to new mutation in probanďs family.

        Key words: congenital microcephaly, blepharoohimosis, palatoschisis, hypospadia, adductal contractures of hip and knees as phenotype of Marden-Walker syndrome due to subtelomeric rearrangement of chromosomes es 8 and 16