Investigation of three patients with the ?ring syndrome?, including familial transmission of ring 5, and estimation of reproductive risks

Summary:Purpose: We analyzed databases on chromosomal anomalies and epilepsy to identify chromosomal regions where abnormalities are associated with clinically recognizable epilepsy syndromes. The expectation was that these regions could then be offered as targets in the search for epilepsy genes.Methods: The cytogenetic program of the Oxford Medical Database, and the PubMed database were used to identify chromosomal aberrations associated with seizures and/or EEG abnormalities. The literature on selected small anomalies thus identified was reviewed from a clinical and electroencephalographic viewpoint, to classify the seizures and syndromes according to the current International League Against Epilepsy (ILAE) classification.Results: There were 400 different chromosomal imbalances described with seizures or EEG abnormalities. Eight chromosomal disorders had a high association with epilepsy. These comprised: the Wolf-Hirschhorn (4p-) syndrome, MillerDieker syndrome (del 17p13.3), Angelman syndrome (del 15q11-q13), the inversion duplication 15 syndrome, terminal deletions of chromosome 1q and 1p, and ring chromosomes 14 and 20. Many other segments had a weaker association with seizures. The poor quality of description of the epileptology in many reports thwarted an attempt to make precise karyotypephenotype correlations.Conclusions: We identified certain chromosomal regions where aberrations had an evident association with seizures, and these regions may be useful targets for gene hunters. New correlations with specific epilepsy syndromes were not revealed. Clinicians should continue to search for small chromosomal abnormalities associated with specific epilepsy syndromes that could provide important clues for finding epilepsy genes, and the epileptology should be rigorously characterized.

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“…Seizures are not a feature of the well-known "cri du chat" (5p deletion) syndrome, nor with chromosome 5 rings (75,76) or duplications (77,78).…”

Section: Chromosomementioning

confidence: 99%

Chromosomal Abnormalities and Epilepsy: A Review for Clinicians and Gene Hunters

et al. 2002

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“…Several investigators described a specific phenotype in a subgroup of patients with autosomal rings independent of which autosome was involved [Côté et al, 1981;Kosztolá nyi, 1987;MacDermot et al, 1990;Freyberger et al, 1991;Migliori et al, 1994]. The major abnormality in those patients is primordial growth failure without malformations and with or without minor anomalies.…”

Section: Introductionmentioning

confidence: 98%

“…Côté et al [1981] proposed the term "ring syndrome" for this group of patients, and more recently Kosztolá nyi reviewed 207 cases with a ring autosome and found that a fifth of the group had the "ring syndrome" phenotype. Most previous reports [McDermott et al, 1977;Zuffardi et al, 1980;Côté et al, 1981;MacDermot et al, 1990;Freyberger et al, 1991;Migliori et al, 1994] have relied on standard cytogenetic banding techniques to exclude deletions in the ring chromosomes. We report on two cases with complete ring (4) and ring (9) chromosomes, respectively, and the "ring syndrome" phenotype.…”

Section: Introductionmentioning

confidence: 99%

Clinical, cytogenetic, and fluorescence in situ hybridization findings in two cases of ?complete ring? syndrome

et al. 1999

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The term "ring syndrome" was proposed to describe a phenotype of growth failure without major malformations due to a ring autosome. The growth failure is thought to be caused by instability of the ring chromosome leading to aneusomy and cell death. Most previous studies of ring chromosomes were based on standard cytogenetic banding techniques and were limited to microscopically detectable deletions in the ring chromosomes. We report on two patients with complete ring (4) and ring (9) chromosomes, respectively. The first was a 15-month-old girl and the second was a 16-month-old boy. They both presented with severe, symmetrical growth failure and normal psychomotor development in the absence of malformations. Their parents had a normal phenotype. The first case had a whorled pattern of hyperpigmentation and hypopigmentation on part of the face and chest, and the second case had a patchy hyperpigmented rash on the trunk. Peripheral blood karyotype of the first patient was 46,XX, r(4)(p16.3q35.2) and of the second 45,XY,-9/46,XY,r(9)(p24q34.3). G-band analysis suggested no loss of material in the ring chromosomes. These findings were confirmed by fluorescence in situ hybridization (FISH) analysis using chromosome-specific subtelomeric probes. The common human telomeric sequences were intact in the first patient but absent in the second patient. The cytogenetic and FISH data in our two cases provide further evidence for the existence of a "complete ring" phenotype independent of the autosome involved. Pigmentary skin changes are a useful clinical sign of mosaicism caused by the ring instability.

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“…While some cases of ring chromosomes have been shown to have occurred with no accompanying deletion [MacDermot et al, 1990;Pezzolo et al, 1993;Sigurdardottir et al, 1999;Borovik et al, 2003;Kosho et al, 2005], we have shown, using array-CGH analysis, that small deletions may be present in rings which appear complete by conventional cytogenetic techniques. Referring to the phenotype of our patient, we believe that we have a combination of 2 conditions: the 'ring syndrome' and the partial deletion 2q37.3 phenotype.…”

Section: Discussionmentioning

confidence: 86%

“…The hypothesis of a 'ring syndrome' without deletion was later confirmed by MacDermot et al [1990], Pezzolo et al [1993], Sigurdardottir et al [1999], Borovik et al [2003], and Kosho et al [2005]. MacDermot et al [1990] also were unable to show the loss of genetic material in 3 cases of ring chromosome 5, using G-, R-and Q-banding techniques and scanning electron microscopy.…”

Section: Discussionmentioning

confidence: 90%

35-Year Follow-Up of a Case of Ring Chromosome 2: Array-CGH Analysis and Literature Review of the Ring Syndrome

Sarri

Douzgou

Kontos

et al. 2015

Cytogenet Genome Res

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Côté et al. [1981] suggested that ring chromosomes with or without deletions share a common pattern of phenotypic anomalies, regardless of which chromosome is involved. The phenotype of this ‘general ring syndrome' consists of growth failure without malformations, few or no minor anomalies, and mild to moderate mental retardation. We reconsidered the ring chromosome 2 case previously published by Côté et al. [1981], and we characterized it by array CGH, polymorphic markers as well as subtelomere MLPA and FISH analysis. A terminal deletion (q37.3qter) of maternal origin of the long arm of the ring chromosome 2 was detected and confirmed by all the above-mentioned methods. Ring chromosome 2 cases are exceedingly rare. Only 18 cases, including the present one, have been published so far, and our patient is the longest reported survivor, with a 35-year follow-up, and the third case characterized by array-CGH analysis.

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Investigation of three patients with the ?ring syndrome?, including familial transmission of ring 5, and estimation of reproductive risks

Cited by 28 publications

References 13 publications

Chromosomal Abnormalities and Epilepsy: A Review for Clinicians and Gene Hunters

Chromosomal Abnormalities and Epilepsy: A Review for Clinicians and Gene Hunters

Clinical, cytogenetic, and fluorescence in situ hybridization findings in two cases of ?complete ring? syndrome

35-Year Follow-Up of a Case of Ring Chromosome 2: Array-CGH Analysis and Literature Review of the Ring Syndrome

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