Complex chromosome 17p rearrangements associated with low-copy repeats in two patients with congenital anomalies.

Department of Human Genetics, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands.
Human Genetics (Impact Factor: 4.52). 08/2007; 121(6):697-709. DOI: 10.1007/s00439-007-0359-6
Source: PubMed

ABSTRACT Recent molecular cytogenetic data have shown that the constitution of complex chromosome rearrangements (CCRs) may be more complicated than previously thought. The complicated nature of these rearrangements challenges the accurate delineation of the chromosomal breakpoints and mechanisms involved. Here, we report a molecular cytogenetic analysis of two patients with congenital anomalies and unbalanced de novo CCRs involving chromosome 17p using high-resolution array-based comparative genomic hybridization (array CGH) and fluorescent in situ hybridization (FISH). In the first patient, a 4-month-old boy with developmental delay, hypotonia, growth retardation, coronal synostosis, mild hypertelorism, and bilateral club feet, we found a duplication of the Charcot-Marie-Tooth disease type 1A and Smith-Magenis syndrome (SMS) chromosome regions, inverted insertion of the Miller-Dieker lissencephaly syndrome region into the SMS region, and two microdeletions including a terminal deletion of 17p. The latter, together with a duplication of 21q22.3-qter detected by array CGH, are likely the unbalanced product of a translocation t(17;21)(p13.3;q22.3). In the second patient, an 8-year-old girl with mental retardation, short stature, microcephaly and mild dysmorphic features, we identified four submicroscopic interspersed 17p duplications. All 17 breakpoints were examined in detail by FISH analysis. We found that four of the breakpoints mapped within known low-copy repeats (LCRs), including LCR17pA, middle SMS-REP/LCR17pB block, and LCR17pC. Our findings suggest that the LCR burden in proximal 17p may have stimulated the formation of these CCRs and, thus, that genome architectural features such as LCRs may have been instrumental in the generation of these CCRs.


Available from: Lisenka E L M Vissers, May 24, 2015
  • [Show abstract] [Hide abstract]
    ABSTRACT: Many deletions of chromosome 17p13.1 have been described, but very few 17p13.1 duplications have been reported yet. Here, we describe the genotype and phenotype of a boy with a duplication of this region. The main clinical features are mild intellectual deficiency, growth retardation, and a typical Silver-Russell syndrome (SRS) appearance with small triangular face, prominent forehead, micrognathia, low-set ears, and clinodactyly. Array-CGH revealed a 586 kb duplication containing many genes with a high neuronal expression. Interestingly, this region covers the minimal critical region including all candidate genes suggested to explain the 17p13.1 microdeletion syndrome. In the neighboring region 17p13.3, deletions and duplications of the same region are each responsible of a specific phenotype. Future case descriptions will show if a similar mechanism applies to the region 17p13.1. The 17p13.1 region contains interesting putative candidate genes that might be involved in the SRS etiology. Additional data are needed to verify the significance of this aberration. © 2012 Wiley Periodicals, Inc.
    American Journal of Medical Genetics Part A 10/2012; 158A(10):2564-70. DOI:10.1002/ajmg.a.35553 · 2.05 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Key Clinical Meassage Patients with rare deletions in 16q12 and a duplication of 17p, both interstitial and de novo. Only seven cases have been described with these deletions and none of them presented other chromosomal abnormalities. The proband showed a complex phenotype with features found in patients with dup17p11.2 syndrome, deletions in 16q12.
    09/2014; 2(6). DOI:10.1002/ccr3.117
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The 1.4Mb tandem-duplication in the PMP22 gene at 17p11.2 usually manifests as hereditary sensorimotor polyneuropathy with foot deformity, sensorineural hearing-loss, moderate developmental delay, and gait disturbance. Hypertelorism and marked phenotypic variability within a single family has not been reported. In a single family, the PMP22 tandem-duplication manifested as short stature, sensorimotor polyneuropathy, tremor, ataxia, sensorineural hearing-loss, and hypothyroidism in the 27 years-old index case, as mild facial dysmorphism, muscle cramps, tinnitus, intention tremor, bradydiadochokinesia, and sensorimotor polyneuropathy in the 31 year-old half-brother of the index-patient, and as sensorimotor polyneuropathy and foot-deformity in the father of the two. The half-brother additionally presented with hypertelorism, not previously reported in PMP22 tandem-duplication carriers. The presented cases show that the tandem-duplication 17p11.2 may present with marked intra-familial phenotype variability and that mild facial dysmorphism with stuck-out ears and hypertelorism may be a rare phenotypic feature of this mutation. The causal relation between facial dysmorphism and the PMP22 tandem-duplication, however, remains speculative.
    03/2012; 27(2):164-7. DOI:10.5001/omj.2012.34