Síndrome de inversión duplicación del cromosoma 15 (INVDUP15) «de novo»: presentación de tres casos clínicos

Abstract

Introduction The chromosome 15 inversion duplication syndrome refers to distinctive clinical findings, such as, early central hypotonia, developmental delay, epilepsy and autistic behaviour. Invdup(15) results from partial 15q tetrasomy and the Prader-Willi syndrome(PWS) region is generally involved. We have analyzed three clinical cases in a Genetics Unit diagnosed with hypotonia and developmental delay. Material and methods Lymphocyte cultures from peripheral blood samples, high resolution karyotype, FISH, DNA isolation from peripheral blood leukocytes, PWS MS-MLPA and microsatellites study. Results The first case showed a karyotype 47,XY+der(15)(q13;p11.2)(pter->q13::p11.2->pter) and a molecular karyotype arr 15q12.1q13(18,432,358-26,658,490)x3 ∼ 4 with an extra 8.23Mb genetic material involving imprinted genes from SPW and Angelman (SA) syndromes region. In the second case there was a karyotype 47, XX, + mar.ish idic (15)(q13)(Acro p-arm ++, D15Z1 ++, D15S10 ++, PML-) and a molecular karyotype arr 15q11.2q13.3(18,432,358-30,230,511)x3 with an approximately 12Mb duplication. The third patient was a carrier of a mosaic double line cell with karyotype 47,XX+ der (15) inv (15)(q11;p11.2) [40%] / 46,XX [60%]. In the three cases the SPW region was analysed using a modified methylation pattern and all resulted from a invdup(15) «de novo» genetic defect. Discussion Although it is difficult to establish a phenotype-genotype correlation in invdup (15) cases, most recent genetic techniques should provide information for the clinical diagnosis in these patients.