Monozygotic twins discordant for Goldenhar syndrome

Verona, Leonardo Lima; Damian, Nicholas Godoy Canazza; Pavarina, Lucimara P.; Ferreira, Cristina Helena Faleiros; Melo, Débora Gusmão

doi:10.2223/jped.1441

Cited by 22 publications

(24 citation statements)

References 16 publications

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“…This exchange includes the exchange of haematopoietic stem cells (HSCs) present in circulating blood. 16,35 However, for two reasons this theory does not explain the observation that an equivalent and severe hypomethylation was detected in leukocyte DNA of both the affected and unaffected twins.…”

Section: Excess Of Hil In Twinsmentioning

confidence: 93%

Lessons from BWS twins: complex maternal and paternal hypomethylation and a common source of haematopoietic stem cells

et al. 2009

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The Beckwith -Wiedemann syndrome (BWS) is a growth disorder for which an increased frequency of monozygotic (MZ) twinning has been reported. With few exceptions, these twins are discordant for BWS and for females. Here, we describe the molecular and phenotypic analysis of 12 BWS twins and a triplet; seven twins are MZ, monochorionic and diamniotic, three twins are MZ, dichorionic and diamniotic and three twins are dizygotic. Twelve twins are female. In the majority of the twin pairs (11 of 13), the defect on chromosome 11p15 was hypomethylation of the paternal allele of DMR2. In 5 of 10 twins, there was additional hypomethylation of imprinted loci; in most cases, the loci affected were maternally methylated, but in two cases, hypomethylation of the paternally methylated DLK1 and H19 DMRs was detected, a novel finding in BWS. In buccal swabs of the MZ twins who share a placenta, the defect was present only in the affected twin; comparable hypomethylation in lymphocytes was detected in both the twins. The level of hypomethylation reached levels below 25%. The exchange of blood cells through vascular connections cannot fully explain the degree of hypomethylation found in the blood cell of the non-affected twin. We propose an additional mechanism through which sharing of aberrant methylation patterns in discordant twins, limited to blood cells, might occur. In a BWS-discordant MZ triplet, an intermediate level of demethylation was found in one of the non-affected sibs; this child showed mild signs of BWS. This finding supports the theory that a methylation error proceeds and possibly triggers the twinning process.

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Section: Excess Of Hil In Twinsmentioning

confidence: 93%

Lessons from BWS twins: complex maternal and paternal hypomethylation and a common source of haematopoietic stem cells

et al. 2009

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“…However, its frequency has been shown to be very variable, oscillating between 5% and 58%. [4][5][6][7][8][9][10][11][12][13][14] Thus, in face of the importance of the clinical characterization of these patients, and the paucity of related studies in our country, [15][16][17] our objective was to verify the frequency and types of congenital heart defects in a sample of patients with OAVS, correlating the presence of this malformation with other clinical characteristics and evolution. This study included only patients submitted to chromosome evaluation through karyotype exam by GTG banding and who presented phenotypical abnormalities in at least two or the following regions: 1) orocraniofacial, 2) ocular, 3) auricular and 4) vertebral.…”

Section: Original Article Introductionmentioning

confidence: 99%

Espectro óculo-aurículo-vertebral e malformações cardíacas

Rosa¹,

Dall'Agnol²,

Zen³

et al. 2010

Rev. Assoc. Med. Bras.

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Objective. To verify the frequency and types of congenital heart defects in a sample of patients with oculo-auriculo-vertebral spectrum (OAVS), in order to correlate the presence of these defects with other clinical characteristics and evolution. MethOds. The sample comprised 33 subjects, all attended in the same center, between January 1975 and December 2007. Twenty two of them were male and eleven female with ages ranging from 1 day to 17 years old. All presented normal karyotype by GTG-Banding. A data collection related to their clinical history, physical examination and result of complementary evaluations was performed. Results. Cardiac abnormalities were observed in 13 patients (39.4%). Of these, 5 (38.5%) were conotruncal, tetralogy of Fallot being the main malformation (n=2). Unusual anomalies identified included cor triatriatum and double inlet left ventricle. Significant differences among the clinical characteristics of the group with and without heart defect were only verified in relation to age at first evaluation that was lower in subjects with cardiac malformations. Five patients died, four of them carriers of congenital heart defects. cOnclusiOn. Cardiac malformations, mainly of the conotruncal and septal types, are frequent among patients with OAVS. The frequency found in our study was statistically similar to the one found in the majority of works described in literature, which ranges from 18 to 58%. Congenital heart defects also represent the main cause of death of these subjects. Thus, a cardiac evaluation should always be performed in these patients, especially at an early age.

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“…Some cases of Goldenhar syndrome have a genetic basis, however, this cannot be so for every case of the condition due to its highly sporadic occurrence and also reports of monozygotic twins of which only one twin has Goldenhar Syndrome [1,3,9]. Other explanations put forward to explain how the condition might arise include vascular disruption during morphogenesis in utero [3], gestational diabetes [10,11] and assisted conception treatments involving ovarian stimulation [4,5].…”

Section: Discussionmentioning

confidence: 99%

“…Other explanations put forward to explain how the condition might arise include vascular disruption during morphogenesis in utero [3], gestational diabetes [10,11] and assisted conception treatments involving ovarian stimulation [4,5].…”

Section: Discussionmentioning

confidence: 99%

“…Although the aetiology of the condition is unknown, some familial cases with autosomal dominant or autosomal recessive inheritance have been described. However Goldenhar Syndrome appears to be largely sporadic, has been reported in discordant monozygotic twins [3] and it has been suggested that such congenital anomalies are associated with assisted conception treatments such as In-Vitro Fertilisation (IVF) and Intra-Cytoplasmic Sperm Injection (ICSI) [4,5], bringing into question a genetic basis for the syndrome.…”

Section: Introductionmentioning

confidence: 99%

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