A new case of de novo 11q duplication in a patient with normal development and intelligence and review of the literature

Abstract

A new case of 11q interstitial duplication is reported in a patient with mild dysmorphic features but normal development. Chromosome analysis revealed a de novo 11q dup(11)(q14.1q21) on G banding and FISH studies. Additional molecular genetic studies revealed a similar but more distal duplication at the level of 11q21q23.1. Previous cases of isolated 11q duplication that overlapped with this case were associated with a wide variety of clinical findings and variable developmental disability. These cases all included additional material not duplicated in this patient. The current case represents the first de novo case of 11q duplication with normal development suggesting that the segment between 11q14.1 and 11q21 contains few genes that are dose sensitive. Review of other cases that have used conventional cytogenetic resolution studies suggests that the band 11q13.5 may contain genes contributing to the developmental disabilities in the cases previously reported with proximal 11q duplication. Differences between conventional cytogenetic techniques and newer molecular genetic studies are expected. These newer techniques will help refine prognosis and counseling for families in the future.

Deficiencies in the region syntenic to human 21q22.3 cause cognitive deficits in mice

“…On the other hand, if the rearranged interval does not contain dosage sensitive genes, deletion or duplication should not lead to mental retardation-related phenotypes. Such cases have been observed in humans and mice (Besson et al 2007; Gilmore et al 2001; Zarate et al 2007). Also, in our preliminary study, the duplication of human chromosome 21 syntenic region on Mmu10 did not cause impairment in the Morris water maze test or the contextual fear conditioning test (Yu et al, unpublished data).…”

Partial trisomy of 11q23.3‐q25 inherited from a maternal low‐level mosaic unbalanced translocation

“…For example, Emanuel syndrome is the result of partial trisomy of chromosome 11q23‐qter, combined with duplication of 22q10‐q11 [Choudhary et al, ; Ohye et al, ]. Partial trisomy of 11q without a copy number change of another chromosome is very rare [Zarate et al, ; Gohring et al, ; Burnside et al, ; Kayhan et al, ]. Given the rarity of this syndrome and minimal use of high‐resolution techniques, such as array CGH, the genotype‐phenotype correlation of partial trisomy of 11q has been poorly defined to date.…”

Chromosomal‐array analysis reveals partial 11q duplication and partial 12p deletion in a mildly affected case

“…The clinical abnormalities of trisomy 11q were detailed in 1977 by Francke et al [] who recognized it as “duplication 11(q21/23(qter) syndrome”. The highly variable phenotype can found an explanation by the different size of the duplicated region and/or the autosome involved [Yelavarthi and Zunich, ; Klaassens et al, ; Zarate et al, ]. The comparison between the clinical features of previously reported pure partial trisomy 11q cases and the case reported herein is shown in Table .…”

“…To date, both pure partial trisomy 11q [Greig et al, ; Forsythe et al, ; Pfeiffer and Schutz, ; De Die Smulders and Engelen, ; Delobel et al, ; Zhao et al, ; Yelavarthi and Zunich, ; Partida‐Perez et al, ; Zarate et al, ; Zimberg‐Bossira et al, ] as well as partial trisomy 11q accompanied by other chromosomal anomalies have been reported [Klaassens et al, ; Lall et al, ]. The breakpoint regions in some cases, such as the one reported by Zhao et al [] as 11q13–25, Zarate et al [] as 11q14.1–q21, and Lall et al [] as 11q14–q25 were almost identical to the case reported herein. The clinical abnormalities of trisomy 11q were detailed in 1977 by Francke et al [] who recognized it as “duplication 11(q21/23(qter) syndrome”.…”