Pure and complete 12p trisomy due to a maternal centric fission of chromosome 12

Abstract

Pure and complete 12p trisomy are rare. Here, we report on a unique patient with trisomy 12p syndrome due to centric fission of maternal chromosome 12. Conventional cytogenetic and fluorescence in situ hybridization (FISH) techniques revealed the proposita's karyotype to be 47,XX,+fis(12)(p10)mat whereas the maternal one was 47,XX,-12,+fis(12)(p10),+fis(12) (q10). This is the first report on centric fission of chromosome 12 leading to stable telocentrics, each with a fully functional centromere. Our observation shows that the centric fission of chromosome 12 can be a new mechanism for generation of a partial centromere and trisomy 12p syndrome.

Duplication 12p and Pallister–Killian syndrome: A case report and review of the literature toward defining a Pallister–Killian syndrome minimal critical region

“…In addition to the new case reported here, we identified 21 reports describing a total of 26 individuals with 12p duplications of varying sizes (15 cases were partial 12p duplication, one case had partial 12p triplication and 10 cases had duplication of the entire 12p) [Armendares et al, 1975; Biederman et al, 1977; Tenconi et al, 1977; Hansteen et al, 1978; Parslow et al, 1979; Dallapiccola et al, 1980; Stengel‐Rutkowski et al, 1981; Ray et al, 1985; Rivera et al, 1987; Tayel et al, 1989; Pfeiffer et al, 1992; Zelante et al, 1994; Allen et al, 1996; Rauch et al, 1996; Back et al, 1997; Rivera et al, 1999; Tekin et al, 2001; Zumkeller et al, 2004; De Gregori et al, 2005; Tsai et al, 2005; Eckel et al, 2006; Liang et al, 2006; Cetin et al, 2011]. Ages of the patients described in the previously published case reports ranged from birth to 34 years.…”

Prenatal diagnosis of a fetus with a de novo trisomy 12p by array-comparative genomic hybridization (array-CGH)

“…Pure and complete trisomy 12p is very rare (Cetin et al, 2011). Trisomy 12p was characterized by profound psychomotor and mental retardation, generalized hypotonia, seizure, and facial dysmorphism.…”

Complete trisomy 10p resulting from an extra stable telocentric chromosome

“…Centric fission of a chromosome occurs after a break in the centromeric region resulting in the separation of the centromere into two portions, and consequently the formation of two stable telocentric chromosomes [Perry et al, 2004]. Only a few individuals with stable centric fission originating from different chromosomes have been documented so far [Janke, 1982; Del Porto et al, 1984; Shim et al, 2007; Cetin et al, 2011]. There is one report of a centric fission of chromosome 10 in a healthy woman who had two pregnancies with trisomy 10p, but there was no evidence of any clinical presentation or a record of the outcome of these pregnancies [Perry et al, 2005].…”