objective hereditary spastic paraplegia (hsp) is a degenerative disease of genetic origin affecting the corticospinal tracts in the spinal cord. there are three forms of inheritance: autosomal dominant hsp, autosomal rececive hsp and x-linked hsp. this disease is characterized by progressive spasticity of leg muscles with varying degrees of stiffness and weakness of other muscle groups. in this...

Anxiety comprises many clinical descriptions and phenotypes. A genetic predisposition to anxiety is undoubted; however, the nature and extent of that contribution is still unclear. Extensive genetic studies of the serotonin (5-hydroxytryptamine, 5-HT) transporter (5-HTT) gene have revealed how variation in gene expression can be correlated with anxiety phenotypes. Complete genome-wide linkage s...

Although in the broadly defined genetic algebra, multiplication suggests a forward direction of from parents to progeny, when looking from the reverse direction, it also suggests to us a new algebraic structure-coalge- braic structure, which we call genetic coalgebras. It is not the dual coalgebraic structure and can be used in the construction of phylogenetic trees. Math- ematically, to constr...

leukodystrophies are familial disorders with onset usually in infancy or childhood. the name comes from the greek leuko meaning white and dystrophy meaning imperfect growth or development. leukodystrophy is a progressive, genetic disorder with an autosomal recessive or x-linked mode of inheritance. the clinical features consist of motor dysfunction with varying degrees of cognitive decline. mag...

The interaction of random gene drift and selection was studied by computer simulation for two quantitative traits, which were considered to approximate stature and skin color dlfferences in human populations. The expected effects of gene drift, fixation of alleles and reduction of genotypic and phenotypic variances, were found in the simulation. Stabilizing selection, which seems to be the type...

The following fictional case is intended as a learning tool within the Pathology Competencies for Medical Education (PCME), a set of national standards for teaching pathology. These are divided into three basic competencies: Disease Mechanisms and Processes, Organ System Pathology, and Diagnostic Medicine and Therapeutic Pathology. For additional information, and a full list of learning objecti...