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Abnormalities associated with the
q11-q13 region of human chromosome 15 and a case report of an intrachromosomal triplication
of 15q11-q13. |
| The rapid evolution of cytogenetic and molecular technologies over recent years is well illustrated by the progressive characterization of the complex molecular and genetic features of the q11-q13 region of human chromosome 15. This report reviews the clinical, cytological and molecular features of of several disorders associated with this region. This is followed by a case report of a de novo intrachromosomal triplication of 15q11-q13 in a 26-year-old female with a history of mental retardation, seizure disorder, behavioral problems and mild dysmorphic features. Phenotypic and molecular cytogenetic findings of this patient are compared with those of five patients previously reported to have an intrachromosomal triplication of 15q11-q13, and with the clinical features described in Prader-Willi syndrome, Angelman syndrome, intrachromosomal duplication of 15q11-13 and inv dup (15). The potential effects of imprinting and dosage on phenotype, proposed mechanisms for the development of intrachromosomal triplication of 15q11-q13 and genetic counseling issues are discussed. | |
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The genetics of frontotemporal dementia, a late-onset neurodegenerative disorder by Masters of Science in Genetic Counseling |
| Frontotemporal Dementia (FTD) is a is a non-Alzheimer dementia involving local degeneration of the frontal lobe and/or temporal lobes of thebrain. It is characterized by early changes in personality and disruption of speech behavior, with progressive deterioration of cognition and premature death. Previous studies have linked FTD to chromosome 17q21-22 with autosomal dominant inheritance within these linked families. In this study, I set out to determine the familial nature of FTD, and potential modes of inheritance. Interviews were conducted with families of individuals who were diagnosed with FTD at UCLA/Harbor Medical Center. Three general categories of inheritance patterns were observed among the 41 families. 57.9% of the cases appear to be familial (on the assumption of quite variable expression of the disease), and 86.4% of those families have patterns consistent with autosomal dominant inheritance. This assessment will be tested by linkage analysis in the future. | |
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Nonketotic hyperglycinemia: a case report |
| Nonketotic hyperglycinemia (NKHG) is devastating neurological
condition that is caused by a molecular lesion in the glycine cleavage system.
These defects result in the accumulation of toxic levels of glycine in the plasma
and cerebrospinal fluid. The diagnosis of this recessively inherited condition
is established by calculating the cerebrospinal fluid:plasma glycine ratio, and may
be confirmed by measuring the activity of the glycine cleavage system in the liver
tissue. Because of poor prognosis for this condition, the birth of an affected child opens a great deal of emotional feelings such as shock, guilt, and grief. Subsequent pregnancies would be expected to create a tremendous amount of anxiety, anxiousness and fear of birth of another child with NKHG. Consequently, most couples with a pregnancy known to be at risk for this condition request prenatal diagnosis. Unfortunately, the biochemical assay used for prenatal diagnosis lacks sensitivity and specificity, and results are often inconclusive. This case report is an example of how a couple who sought prenatal diagnosis, faced and coped with ambiguous prenatal test results. |
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Unusual brain
findings: a case report |
| Isochromosomes have been studied since Darlington first reported their existence in plants in 1939. They were found in humans as early as 1960. With the advent of chromosome banding and later fluorescence in situ hybridization, isochromosomes could be described with certainty. This case report extends previous discussions of the characteristics of unusual associated brain findings in this proband. | |