Monozygotic twinning and structural defects

Schinzel, Albert; Smith, David W.; Miller, James R.

doi:10.1016/s0022-3476(79)80278-4

Cited by 494 publications

(265 citation statements)

References 30 publications

Supporting

Mentioning

238

Contrasting

Unclassified

Order By: Relevance

“…In general, monozygotic twins are concordant for structural anomalies in only 5-20% of cases [Schinzel et al, 1979]. In particular, cardiac defects, which are more common in monozygotic twins, usually affect only one of the pair [Burn and Corney, 1984].…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Monozygotic twins with a severe form of Alagille syndrome and phenotypic discordance

et al. 2002

View full text Add to dashboard Cite

Alagille syndrome is an autosomal dominant disorder affecting multiple organ systems, predominantly the liver, heart, skeleton, eye, face, and kidney. The phenotype in Alagille syndrome is highly variable both within and between families. We report monozygotic twins with Alagille syndrome concordant for a mutation in Jagged1 but discordant for clinical phenotype. The twins' monozygosity was confirmed by molecular testing. A de novo splice site mutation was identified in exon 6 (1329 + 2T → G) in both children. Both twins display a severe form of Alagille syndrome; however, one twin has a severe pulmonary atresia with mild liver involvement, while the other has tetralogy of Fallot and severe hepatic involvement, which has required liver transplantation. Potential mechanisms for phenotypic variability among monozygotic twins are discussed. This is the first reported case of discordance in phenotype in monozygotic twins with Alagille syndrome. This case implies that genotypic variations alone do not explain the clinical variability seen in Alagille syndrome and supports the contributory role of nongenetic factors in phenotype determination. © 2002 Wiley‐Liss, Inc.

show abstract

Section: Discussionmentioning

confidence: 99%

“…The presence of vascular anastomoses within a monochorionic placenta may also contribute to unequal blood flow and discordant structural anomalies [Yamagishi et al, 1998]. Certain structural defects in monozygotic twins may result from physical constraint secondary to in utero crowding [Schinzel et al, 1979].…”

Section: Discussionmentioning

confidence: 99%

Monozygotic twins with a severe form of Alagille syndrome and phenotypic discordance

et al. 2002

View full text Add to dashboard Cite

show abstract

“…However, it is interesting to point out that craniofacial anomalies in general (caused by either malformation or deformation) seem to be more frequent in monozygotic twins 31 . It was also suggested that twining, per se, could be considered a congenital malformation 32 .…”

Section: Discussionmentioning

confidence: 99%

A clinical study of 31 individuals with midline facial defects with hypertelorism and a guideline for follow-up

Gil-da-Silva-Lopes

Maciel‐Guerra

2007

Arq. Neuro-Psiquiatr.

View full text Add to dashboard Cite

In order to contribute to clinical delineation of midline facial defects with hypertelorism (MFDH) and to etiologic diagnosis of the isolated form, 31 patients with MFDH unaffected by known syndromic associations were evaluated. Group A included patients personally examined by the authors, while Group B included those previously evaluated by other geneticists. Among the 14 patients from Group A, there were 7 with distinct pictures of multiple congenital anomalies. In Group B, 5 of the 17 patients also exhibited a distinct pattern of defects. Among isolated MFDH, there was association with anomalies of the skull and facial bones (13/14), otorhinologic (11/16), central nervous system (9/16), and ocular (6/7), and audiologic (3/16); 1/3 of the cases had a relevant gestational intercurrences. Isolated FNM may have involvement of environmental components in some cases; the possibility of a syndromic picture should be extensive investigated. Follow-up of such patients must include the examinations herein performed.

show abstract

“…7 In the majority of cases, monozygotic twins share a single placenta and so vascular disruptions are common, which explains the divergent clinical presentation at birth of individuals who are genetically identical. 13 The etiology of Goldenhar syndrome is itself related to vascular disruption, particularly of the stapedial artery (which is a branch of the internal carotid) and the external carotid, which alters the morphogenesis of structures derived from the first and second branchial arches, and it is from this that all of the clinical manifestations stem. 7 It is believed that Goldenhar syndrome is part of a more complex clinical presentation of first and second branchial arches defects, most often known as oculoauriculo-vertebral spectrum and characterized by the presence of additional vertebral anomalies and epibulbar dermoids.…”

Section: Discussionmentioning

confidence: 99%

Síndrome de Goldenhar: relato de um caso com discordância em gêmeas monozigóticas

Verona¹,

Damian²,

Pavarina³

et al. 2006

J. Pediatr. (Rio J.)

View full text Add to dashboard Cite

Objective: To report on a pair of monozygotic female twins discordant for Goldenhar syndrome. Description:The affected twin was a girl, who was delivered by caesarean section at 35 weeks gestation. Her birth weight was 2,170 g, length 42.5 cm, head circumference 30 cm and her APGAR scores were 3/7. After birth the child developed severe respiratory distress and had to be moved to the neonatal intensive care unit (ICU). The other twin was a girl, born weighing 3,200 g with a length of 49 cm, head circumference of 34 cm and Apgar scores of 8/10. She was transferred to the mother-baby unit soon after birth and was discharged two days later. There was no consanguinity between the twins parents, who were young and healthy at the time of their conception. The affected childs dysmorphic features included left hemifacial microsomia, severe micrognathia, abnormal ears, bilateral preauricular tags and epibulbar dermoid in the right eye. She developed obstructive apnea due to micrognathia and required tracheostomy. Abdominal and cranial ultrasound findings were normal, as was an ophthalmological assessment. Spine x-ray showed hemivertebra at T9 and T10. An echocardiogram showed Tetralogy of Fallot. GTG-banded karyotyping was performed on peripheral blood cells and revealed 46,XX. Zygosity testing established the pair of twins to be monozygotic with a probability greater than 99:1.Comment: Goldenhar syndrome was diagnosed in one of the twins described here. There are several reports of twins discordant for this disorder and therefore non-genetic factors may also play an important role, for instance vascular disruption during morphogenesis.

show abstract

Monozygotic twinning and structural defects

Cited by 494 publications

References 30 publications

Monozygotic twins with a severe form of Alagille syndrome and phenotypic discordance

Monozygotic twins with a severe form of Alagille syndrome and phenotypic discordance

A clinical study of 31 individuals with midline facial defects with hypertelorism and a guideline for follow-up

Síndrome de Goldenhar: relato de um caso com discordância em gêmeas monozigóticas

Contact Info

Product

Resources

About