Chromosome 20p inverted duplication deletion identified in a Thai female adult with mental retardation, obesity, chronic kidney disease and characteristic facial features

We report on a 21-year-old Thai woman presenting with mental retardation, developmental delays, selective mutism, distinctive facial features, sensorineural hearing loss, single right kidney, uterine didelphys and obesity. A longitudinal clinical course beginning in childhood revealed excessive weight gain, poor language skills and poor school performance. Chronic kidney disease stage 4, with elevated blood pressure, was first noted in adulthood. Array comparative genomic hybridization detected a copy loss at 20p13 co-existing with a copy gain at 20p13-20p11.22. A conventional cytogenetic study revealed the complex structural rearrangement of chromosome 20 [der (20) dup (20) (p11.2p13) del (20) (p13.pter)]. A FISH analysis, using probes against duplication and deletion regions, confirmed that there was an inverted duplication of p11.2-p13 and a deletion in the subtelomere region. Previous reports have identified this cytogenetic characterization in a Caucasian boy. Therefore, this is the first reported case of chromosome 20p inverted duplication deletion syndrome in an adult from the Southeast Asian population group.