RESUMEN
One of the primary goals in medical genetics is a precise clinical definition of chromosomal diseases. This is now possible because of the increased number of case reports and new techniques. A male patient, without a clear-cut syndrome, was cytogenetically investigated. Chromosomal analysis showed a small unidentified bisatellited supernumerary marker. In situ hybridization with a biotin-labeled DNA probe for the chromosome 15 centromere (D15Z1) demonstrated that the marker was derived from chromosome 15. Hybridization with the Prader-Willi Syndrome Cosmid biotinylated probe (localized to band 15q11-q13) showed a signal on both ends suggesting a marker with a symmetrical inv dup(15) and a breakpoint localized in q13. It was then possible to define the karyotype as: 47,XY,+ inv dup(15) (pter-q13::q13-pter). All cases of inv dup(15) reported in the literature were reviewed, paying particular attention to the different breakpoints involved, in order to provide a better clinical definition of this syndrome.
Asunto(s)
Inversión Cromosómica , Cromosomas Humanos Par 15 , Familia de Multigenes/genética , Adolescente , Humanos , Hibridación Fluorescente in Situ , Cariotipificación , Masculino , FenotipoRESUMEN
We report two related patients, presenting duplication 20p, with a characteristic phenotype including normal growth pattern, mental and psychomotor retardation, reduced motor coordination, poor language development, round face and prominent cheeks, vertebral and dental anomalies, and renal malformations. Familial chromosome analysis showed a balanced translocation t(20;21)(p11;q22) in three members of the family. These cases, together with those previously reported in the literature, allow us to make a better delineation of the duplication 20p syndrome, identifying more clearly the symptoms that must be considered as characteristic of this clinical picture.