Anticipation (genetics)

About: Anticipation (genetics) is a research topic. Over the lifetime, 669 publications have been published within this topic receiving 21784 citations. The topic is also known as: Genetic Anticipation & Anticipation, Genetic.

Juvenile Huntington disease.

Abstract: Huntington disease (HD) is a dominantly inherited neurodegenerative disorder related to expansion of a triplet repeat sequence in the huntington gene on chromosome 4. Adult HD usually presents with chorea and personality changes. Juvenile HD is far less common and presents with parkinsonism, dystonia and seizures. We report a case of juvenile HD, showing extreme anticipation, in which diagnosis was delayed because of failure to recognise the significance of the family history and the characteristic clinical and radiologic features of this condition.

Knowledge, views, and experience of 25 women with myotonic dystrophy.

Abstract: Twenty-five affected women of reproductive age known to the North West Regional Genetics Family Register (NWRGFR) were interviewed. A semistructured questionnaire, completed by the interviewer, was used to assess understanding and experience of the clinical and genetic aspects of myotonic dystrophy (MD) and attitudes to prenatal diagnosis (PND). Characteristic features of MD (muscle weakness and wasting and myotonia) were well known. Knowledge of other features and complications reflected experience. All subjects were aware that MD is inherited, but only 56% (14/25) knew the risk to their own children and subjects tended to overestimate this risk. Anticipation and maternal transmission of congenital myotonic dystrophy (CMD) were often misunderstood. Almost half of the subjects (12/25) perceived themselves to be moderately or severely affected and 40% (10/25) felt that their symptoms restricted daily life. Feelings of devastation, depression, worry about the future, and guilt at the risk of transmission to their children were described. Many subjects (10/25) said that the worst aspect of MD is the risk of transmission to their children. Over half (14/25) said that the risk of transmitting MD had influenced or would influence their own reproduction. Three-quarters of subjects who felt that MD had influenced their reproductive decisions (9/12) chose to limit their family or have no children; only 25% (3/12) requested PND. Subjects felt that the lack of information concerning clinical severity made PND for MD difficult to consider.

Familial autosomal dominant dopa responsive Parkinson's disease in three living generations showing extreme anticipation and childhood onset.

Abstract: We describe a three generation family with Parkinson's disease showing autosomal dominant inheritance with extreme anticipation. Familial Parkinson's disease in three living generations is extremely rare, and anticipation is an unusual and interesting feature. Anticipation was shown in all generations and may have involved previous generations. Some cases of familial Parkinson's disease may therefore involve a trinucleotide repeat gene as part of the causal mechanism.

Generation or birth cohort effect on cancer risk in Li–Fraumeni syndrome

Abstract: Genetic anticipation is the increased incidence, earlier onset, or increased severity of a disease in successive generations. Before the biological basis of anticipation had been demonstrated, the phenomenon was thought to be due to sampling bias, epigenetic effects, gene conversion, or recombinant events. Since then, the biologic basis for anticipation in a number of neurodegenerative disorders has been shown to be attributable to trinucleotide repeat instability, with expansion of repeats clearly correlated with an earlier age of onset. Recently, telomere shortening has been suggested as the mechanism for anticipation in the autosomal dominant form of dyskeratosis congenita, attributable to mutations in the TERC gene, leading to dysfunctional telomeres (Vulliamy et al. 2004). However, the pattern of anticipation has been observed in other disorders, including cancers, for which no genetic defect has been identified. In this study, we assess the apparent generation effect on cancer incidence in ten extended families with P53 germline mutation, identified through probands diagnosed with childhood sarcoma. The probands were from two sets of systematically ascertained sarcoma patients treated at the University of Texas M. D. Anderson Cancer Center between 1944 and 1982. From those overall studies, we have identified ten kindreds having germline P53 mutations in more than one generation. We compared the cancer incidence in members of successive generations of these families with P53 mutations (carriers) and with no P53 mutations (noncarriers). In carriers, cancer incidence increased in succeeding generations; there was no evidence for this effect in noncarriers; however, the noncarrier population was too small to rule it out. The apparent lack of increase in incidence in noncarriers argues against a cohort effect explaining the increase in carriers.