Russell-Silver syndrome and Wilms tumor

Functional roles of CTCF in breast cancer

CTCF, Zinc-finger protein, has been identified as a multifunctional transcription factor that regulates gene expression through various mechanisms, including recruitment of other co-activators and binding to promoter regions of target genes. Furthermore, it has been proposed to be an insulator protein that contributes to the establishment of functional three-dimensional chromatin structures. It can disrupt transcription through blocking the connection between an enhancer and a promoter. Previous studies revealed that the onset of various diseases, including breast cancer, could be attributed to the aberrant expression of CTCF itself or one or more of its target genes. In this review, we will describe molecular dysfunction involving CTCF that induces tumorigenesis and summarize the functional roles of CTCF in breast cancer.

Prevalence of Café-au-Lait Spots in children with solid tumors

Cafe-au-lait maculae (CALM) are frequently observed in humans, and usually are present as a solitary spot. Multiple CALMs are present in a smaller fraction of the population and are usually associated with other congenital anomalies as part of many syndromes. Most of these syndromes carry an increased risk of cancer development. Previous studies have indicated that minor congenital anomalies may be more prevalent in children with cancer. We investigated the prevalence of CALMs in two samples of Brazilian patients with childhood solid tumors, totaling 307 individuals. Additionally, 176 school children without diagnosis of cancer, or of a cancer predisposing syndrome, were investigated for the presence of CALMs. The prevalence of solitary CALM was similar in both study groups (18% and 19%) and also in the group of children without cancer. Multiple CALMs were more frequently observed in one of the study groups (Z = 2.1). However, when both groups were analyzed together, the significance disappeared (Z = 1.5). The additional morphological abnormalities in children with multiple CALMs were analyzed and compared to the findings observed in the literature. The nosologic entities associated with CALMs are reviewed.

Genomic imprinting syndromes and cancer

Genomic imprinting represents a form of epigenetic control of gene expression in which one allele of a gene is preferentially expressed according to the parent-of-origin of the allele. Genomic imprinting plays an important role in normal growth and development. Disruption of imprinting can result in a number of human imprinting syndromes and predispose to cancer. In this chapter, we describe a number of human imprinting syndromes to illustrate the concepts of genomic imprinting and how loss of imprinting of imprinted genes their relationship to human neoplasia.

Methylation profiling in individuals with Russell-Silver syndrome

Russell-Silver syndrome (RSS) is a heterogeneous disorder associated with pre- and post-natal growth restriction and relative macrocephaly. Involvement of imprinted genes on both chromosome 7 and 11p15.5 has been reported. To further characterize the role of epimutations in RSS we evaluated the methylation status at both 11p15.5 imprinting control regions (ICRs): ICR1 associated with H19/IGF2 expression and ICR2 (KvDMR1) associated with CDKN1C expression in a series of 35 patients with RSS. We also evaluated methylation at the promoter regions of other imprinted genes involved in growth such as PLAGL1 (6q24), GCE (7q21), and PEG10 (7q21) in this series of 35 patients with RSS. Thirteen of the 35 patient samples, but none of 22 controls, showed methylation levels at ICR1 that were more than 2 SD below the mean for controls. Three RSS patients were highly methylated at the SCGE promoter, all of which were diagnosed with upd(7)mat. To identify further potential global methylation changes in RSS patients, a subset of 22 patients were evaluated at 1505 CpG sites by the Illumina GoldenGate methylation array. Among the few CpG sites displaying a significant difference between RSS patients and controls, was a CpG associated with the H19 promoter. No other sites associated with known imprinted genes were identified as abnormally methylated in RSS patients by this approach. While the association of hypomethylation of the H19/IGF2 ICR1 is clear, the continuous distribution of methylation values among the patients and controls complicates the establishment of clear cut-offs for clinical diagnosis.

Surgical closure of an atrial septal defect in an 11-year-old girl with Silver-Russell syndrome

Silver-Russell syndrome is a congenital disease characterized by severe growth retardation and variable dysmorphic features such as a small triangular face, micrognathia, asymmetry (usually of the limbs), syndactyly and clinodactyly. We report a rare case of a girl with extremely low body weight, short stature and an atrial septal defect, who underwent successful surgical repair of the heart abnormality.

Syndromes and constitutional chromosomal abnormalities associated with Wilms tumour

Wilms tumour has been reported in association with over 50 different clinical conditions and several abnormal constitutional karyotypes. Conclusive evidence of an increased risk of Wilms tumour exists for only a minority of these conditions, including WT1 associated syndromes, familial Wilms tumour, and certain overgrowth conditions such as Beckwith-Wiedemann syndrome. In many reported conditions the rare co-occurrence of Wilms tumour is probably due to chance. However, for several conditions the available evidence cannot either confirm or exclude an increased risk, usually because of the rarity of the syndrome. In addition, emerging evidence suggests that an increased risk of Wilms tumour occurs only in a subset of individuals for some syndromes. The complex clinical and molecular heterogeneity of disorders associated with Wilms tumour, together with the apparent absence of functional links between most of the known predisposition genes, suggests that abrogation of a variety of pathways can promote Wilms tumorigenesis.

Bilateral reactive lymphoid hyperplasia of the orbit in a child with Russell-Silver syndrome

Russell-Silver syndrome (RSS) primarily includes intrauterine growth retardation, postnatal growth failure, body asymmetry, and craniofacial disproportion. Four types of malignancies have been reported in patients with RSS: craniopharyngioma, testicular seminoma, hepatocellular carcinoma, and Wilms tumor.

Molecular genetic studies of human chromosome 7 in Russell-Silver syndrome

Russell-Silver syndrome (RSS) is a form of congenital short stature characterized by severe growth retardation and variable dysmorphic features. In some RSS individuals, alterations in imprinted genes may be involved because approximately 7% of sporadic patients have been observed to have maternal uniparental disomy (mUPD) of chromosome 7. RSS patients with structural abnormalities of chromosome 7 have also been described. In these individuals the chromosome rearrangement could disrupt the balance of imprinted genes, contribute to a recessive form of RSS, or lead to haploinsufficiency of a crucial developmental gene product. Because the mechanism and molecular defects on chromosome 7 causing RSS are still unknown, we tested our collection of 77 RSS families for mUPD7 and were able to identify three new cases. We also characterized two RSS patients with de novo cytogenetic abnormalities involving the short arm of chromosome 7. One had a partial duplication [46, XX, dup(7)(p12 p14)] and the second contained a paracentric inversion [46, XY, inv(7)(p14 p21)]. Fluorescence in situ hybridization (FISH) mapping revealed that the breakpoints on 7p14 were localized to the same novel gene, C7orf10, which encompasses >700 kb of DNA. We also identified other transcription units from this immediate region, but all seem to be biallelically expressed when using a somatic cell hybrid assay.

Distraction osteogenesis in Silver Russell syndrome to expand the mandible

Distraction osteogenesis is a method commonly used to activate bone regeneration in nonunions and osseous defects and for lengthening procedures of tubular bones. This technique involves the sectioning of a bone and the subsequent deliberate, controlled movement of the opposing sectioned edges to lengthen, widen, or reposition a bone, or all three. In this report, a patient with Silver Russell syndrome and severe mandibular hypoplasia was treated by means of distraction osteogenesis of the midsymphysis to widen the mandible in concert with sagittal-ramus osteotomies to lengthen the mandible. This treatment created significantly increased arch length in the mandible, which was necessary to facilitate the patient's orthodontic treatment. We believe this is the first reported case of distraction osteogenesis to widen the mandible with the use of a tooth-borne appliance.

Silver-Russell syndrome and exclusion of uniparental disomy

Recently, maternal uniparental disomy for the entire chromosome 7 was described in three of 25 Silver-Russell syndrome sporadic cases, yet the etiology of the remaining cases is unclear. Two cases with Silver-Russell syndrome and a balanced translocation involving the 17q25 had been reported. We looked for evidence of genomic imprinting due to uniparental disomy 17 in seven patients with sporadic Silver-Russell syndrome and their parents. Additionally, chromosomes 7, 8, 11 and 20 were studied. Uniparental disomy was ruled out for all these chromosomes in six of seven families; one family was informative only for chromosome 17. Not-withstanding our negative results, it is still possible that uniparental disomy plays a part in this syndrome. A mutation in a Mendelian gene in 17q25 could also account for the Silver-Russell syndrome etiology.