Characterization of a Complex Chromosomal Rearrangement Involving a de novo Duplication of 9p and 9q and a Deletion of 9q

Rearrangements of the distal region of 9p are important chromosome imbalances in human beings. Trisomy 9p is the fourth most frequent chromosome anomaly and is a clinically recognizable syndrome. Kleefstra syndrome, previously named 9q subtelomeric deletion syndrome, is either caused by a submicroscopic deletion in 9q34.3 or an intragenic mutation of EHMT1. We report a Mexican male patient with abnormal development, dysmorphism, systemic anomalies and a complex chromosomal rearrangement (CCR). GTG-banding revealed a 46,XY,add(9)(q34.3) karyotype, whereas array analysis resulted in arr[hg19] 9p24.3p23(203,861-11,842,172)×3, 9q34.3(138,959,881-139,753,294)×3, 9q34.3(139,784,913-141,020,389)×1. Array and karyotype analyses were normal in both parents. Partial duplication of 9p is one of the most commonly detected autosomal structural abnormalities in liveborn infants. A microdeletion in 9q34.3 corresponds to Kleefstra syndrome, whereas a microduplication in 9q34.3 shows a great clinical variability. Here, we present a CCR in a patient with multiple congenital anomalies who represents the first case with partial 9p trisomy, partial 9q trisomy and partial 9q monosomy.