1/128. Variable pathogenicity of exon 43del (FAA) in four Fanconi anaemia patients within a consanguineous family.Four Fanconi anaemia group A (FAA) patients within two related consanguineous families are presented: the propositus (male, 13 years, transplanted at age 10), and his three cousins (one male, 8 years, and two female newborns). Assignment of the patients to FAA was based on the functional complementation analysis by somatic cell hybridization and confirmed by mutation screening showing a homozygous deletion of exon 43 (4267-4404del) in the FAA gene to be present in all four patients. The newborn patients had been diagnosed prenatally by dna analysis. In spite of identical molecular pathology and close familial relationship the clinical phenotypes of the four patients were not concordant. Discordant symptoms included birthweight, pigmentation abnormalities, skeletal, renal and genital abnormalities, whereas microcephaly and possibly the haematological course were concordant. Differences in environmental conditions and/or genetic make-up along with chance effects during development may explain discordant phenotypes despite identical molecular pathology in these patients. However, our results do not rule out the possibility that the exon 43del mutation may have prognostic value for the haematological course of the disease.- - - - - - - - - - ranking = 1keywords = environment (Clic here for more details about this article) |
2/128. twins with different temporal lobe malformations: schizencephaly and arachnoid cyst.The etiology and relationships between different forms of malformations of cortical development are poorly understood. Schizencephaly is generally regarded as unrelated to arachnoid cysts. As part of a systematic study of epilepsy in twins we observed a monozygotic twin pair discordant for temporal lobe epilepsy where the twin with epilepsy had unilateral temporal schizencephaly and periventricular heterotopia. The twin without epilepsy had an arachnoid cyst in the same temporal lobe. Although an incidental association is possible, this observation, together with occasional reports of schizencephaly and arachnoid cysts within one individual, suggests a shared pathogenic mechanism. Schizencephaly can be caused by both genetic and acquired factors. We propose that our observations in this twin pair are best explained by a genetic factor present in both twins, with an additional environmental insult resulting in schizencephaly in only one of the pair.- - - - - - - - - - ranking = 1keywords = environment (Clic here for more details about this article) |
3/128. Discordance for Cornelia de lange syndrome in twins.A male infant, the first-born of twins, with features of Cornealia de lange syndrome is described. His normal twin was discordnat for 3 of the 14 blood loci tested. chromosomes from the affected infant appeared normal. Though the aetiological basis for the Cornealia de lange syndrome remains obscure, most authorities accept genetic rather than environmental causation. The present findings of discordance for Cornelia de lange syndrome in twins support this view but do not clarify the mode of inheritance.- - - - - - - - - - ranking = 1keywords = environment (Clic here for more details about this article) |
4/128. Diprosopus (partially duplicated head) associated with anencephaly: a case report.Craniofacial duplication (diprosopus) is a rare form of conjoined twin. A 16 year old mother with a twin pregnancy delivered one normally formed baby boy and one diprosopus male. The malformed baby was 33 weeks of gestation with a single trunk, normal limbs and various degrees of facial duplication. Of the following structures there were two of each: noses, eyes, ears (and one dimple), mouths, tongues and, with bilateral central cleft lips and cleft palates. This was associated with holoprosencephaly and craniorachischisis. Internal organs showed no duplication. There were multiple congenital anomalies including diaphragmatic hernia, small lungs, two lobes of the right lung, ventricular septal defect, small adrenal gland and small left kidney with short ureter. The body also had a short neck, small chest cavities and kyphosis. X-ray revealed duplication of the vertebral column. The case presented here represents a type II of diprosopia of Rating (1933) and is the least common type reported. We also reviewed 22 recently reported cases of diprosopus. In addition to facial duplication, anencephaly, neural tube defect and cardiac malformations represent the more common congenital abnormalities associated with diprosopus. The pathogenesis of diprosopus is not well understood. Factors that play a role in diprosopus are probably similar to those factors (genetic, environmental and abnormal placental circulation) which affect monozoygotic twins as observed in this case report. Early ultrasonography diagnosis of diprosopus permits one to consider a vaginal therapeutic abortion.- - - - - - - - - - ranking = 1keywords = environment (Clic here for more details about this article) |
5/128. Two feminized male American Indians.Two American Indian males are described who wish to change sex. Both appear to be anatomically normal; one is a monozygotic twin. In both cases, feminine identification began very early in life. In both cases, there were early acceptance and positive reinforcement of the feminine behavior. These two males and the environment in which they live are contrasted with the anthropological literature published decades ago describing the unique Indian tribal role played by feminized males.- - - - - - - - - - ranking = 1keywords = environment (Clic here for more details about this article) |
6/128. Simultaneous onset of idiopathic dilated cardiomyopathy in identical middle-aged twins.Idiopathic dilated cardiomyopathy is a primary myocardial disease which is characterised by left ventricular, or biventricular, dilatation and impaired contractility. The precise aetiology is unknown and the relative contribution of genetic and environmental factors is debated. We report two identical male twins of Caucasian origin with idiopathic dilated cardiomyopathy who presented within a few months of each other.- - - - - - - - - - ranking = 1keywords = environment (Clic here for more details about this article) |
7/128. Class II Division 2 malocclusion: genetics or environment? A case report of monozygotic twins.A pair of monozygotic twins with different malocclusion phenotypes (Class II Division 2 and Class II Division 1) is presented. The case report supports the hypothesis that heredity is not the sole controlling factor in the etiology of Class II Division 2 malocclusion.- - - - - - - - - - ranking = 4keywords = environment (Clic here for more details about this article) |
8/128. ectodermal dysplasia with hypodontia in a set of Nigerian twins--a case report.A set of Nigerian male twins with features of ectodermal dysplasia born to apparently normal parents are presented. The main findings in both children were hypodontia, abnormally shaped teeth and hypotrichosis. The general treatment modalities of the condition, especially in a tropical environment, are discussed.- - - - - - - - - - ranking = 1keywords = environment (Clic here for more details about this article) |
9/128. Two pairs of proven monozygotic twins discordant for familial amyloid neuropathy (FAP) TTR Met 30.Twin studies are an important tool in medical genetics for the evaluation of the relative roles of genetic and non-genetic factors in several diseases. Familial amyloidotic polyneuropathy type I (FAP-I), TTR Met 30, was present in two sets of proven monozygotic (MZ) twins, one from Majorca and the other from portugal. Monozygosity was established by analysis of dna polymorphisms. Both pairs were discordant for age at onset and some clinical manifestations of FAP-I. We reviewed the differences in age at onset and clinical features in both sets and in two other pairs of presumed MZ twins with FAP-I and compared them with those in MZ twin pairs with other Mendelian disorders, such as neurofibromatosis type 1, Huntington's disease, facioscapulohumeral muscular dystrophy, and myotonic dystrophy. We conclude that, in addition to the postulated modifying genes, there must be a significant contribution from non-genetic factors to the phenotypic variability of FAP-I (age at onset and clinical expression), either because of environmental differences or stochastic events during (or after) the twinning process.- - - - - - - - - - ranking = 1keywords = environment (Clic here for more details about this article) |
10/128. coronary artery disease in identical twins.The incidence of coronary artery disease in identical twins is unknown. The knowledge of ischemic heart disease in this patient population is represented by case reports. There is considerable controversy regarding the environmental and genetic factors that play a role in the pathogenesis of this disorder. The natural history of coronary artery disease in an asymptomatic twin with a symptomatic counterpart is unclear. We present a case report and literature review of coronary artery disease in identical twins. On the basis of our patient and the information of other patients, asymptomatic twins of symptomatic counterparts require aggressive assessment and management for occult coronary artery disease.- - - - - - - - - - ranking = 1keywords = environment (Clic here for more details about this article) |
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