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.

The mutation properties of spinal and bulbar muscular atrophy disease alleles.

Abstract: We studied the gene for the trinucleotide repeat disorder X-linked spinal and bulbar muscular atrophy (SBMA) to quantify the spectrum of mutations and gain insight into genetic anticipation. This analysis was performed using single sperm typing from an affected individual. This method allows the quantification of large numbers of meioses and therefore provides accurate information about genetic instability of the CAG repeat expansions which cause SBMA. Among 198 X chromosome-containing sperm cells, 20% had a CAG repeat number equal to the donor's somatic DNA of 49 CAG repeats, 56% were expansions, and 24% contractions. Most of the expansions (84%) and contractions (94%) were between 1 and 3 CAG repeats. These results are consistent with those obtained from one previously studied SBMA patient and reveal greater CAG repeat instability in sperm than in somatic tissue. Our results indicate that in SBMA, in contrast to sperm typing analysis of Huntington's disease, there is relative stability of the CAG repeat number during paternal transmissions and that the spectrum of mutations is narrow. These results are in agreement with the limited available clinical data and suggest that anticipation may not be a significant feature of this disease.

"Shake hands"; diagnosing a floppy infant--myotonic dystrophy and the congenital subtype: a difficult perinatal diagnosis.

Abstract: Myotonic dystrophy is a multi-organ disease inherited in a complicated way. Congenital myotonic dystrophy is a distinct entity with severe symptoms leading to a high rate of perinatal morbidity and mortality. The occurrence of congenital myotonic dystrophy often allows a subsequent diagnosis in the mother with important implications for her life, her further pregnancies and offspring. Genetic principles of anticipation and somatic mosaicism are involved and hamper the prenatal diagnostic possibilities. A family is presented in which maternal myotonic dystrophy and congenital myotonic dystrophy were diagnosed after the third pregnancy. The key features leading to the diagnosis were obstetric history, neonatal hypotonia and asphyxia, facial abnormalities in the mother together with the inability to bury eyelashes and delayed release of grip after shaking hands. The disorder is reviewed with respect to clinical symptoms, pathogenesis and genetics.

Parkin mutation dosage and the phenomenon of anticipation: a molecular genetic study of familial parkinsonism.

Abstract: Background parkin mutations are a common cause of parkinsonism. Possessing two parkin mutations leads to early-onset parkinsonism, while having one mutation may predispose to late-onset disease. This dosage pattern suggests that some parkin families should exhibit intergenerational variation in age at onset resembling anticipation. A subset of familial PD exhibits anticipation, the cause of which is unknown. The aim of this study was to determine if anticipation was due to parkin mutation dosage.

Anticipation in Myotonic Dystrophy: A Parental-Sex-Related Phenomenon

Abstract: We report anticipation in an extensive sample of myotonic dystrophy (MyD) kindreds taken from an epidemiological survey recently conducted in Guipuzcoa, Spain. Analysis of the parent-child pairs ascertained showed a mean anticipation of 2.86 decades (range 0-6). Greater anticipation occurred when the transmissor parent was the mother. These results suggest a possible sex-related effect in the transmission of the MyD gene, and are in agreement with recent discoveries at the molecular level.

Anticipation in an Indo-Canadian family with Crohn's disease.

Abstract: Genetic anticipation, associated elsewhere with monogenic neurological disorders, has been hypothesized to be present in familial forms of Crohn's disease. Usually, with studies of parent-child pairs, the parent who is initially diagnosed is older at the onset of disease than the child. With each successive generation, an apparent increase in disease severity or behaviour occurs. This phenomenon is believed to have a molecular basis. In the present report, an Indo-Canadian family with Crohn's disease is described. In all members of the family, disease was diagnosed only after prolonged residence in Canada, supporting the view that Crohn's disease arises in individuals with a genetic predisposition following exposure to some, as yet unknown, common environmental factor. Three siblings with Crohn's disease, first diagnosed between ages 15 and 27 years, or six to 11 years after arrival in Canada, had phenotypically concordant disease localized in the ileum and colon, with fistulizing complications, including perianal sepsis. Crohn's disease was only diagnosed in the father at the age of 76 years, almost three decades after his arrival in Canada. His disease was localized to the ileum and had a fibrostenosing behaviour. This is the first reported instance of familial Crohn's disease in an immigrant population, illustrating potential biases in genetically based studies of Crohn's disease that rely solely on phenotypic expression.