1.1.2 Pre-natal diagnosis

The type of genetic testing that the majority of us are most likely to come across is still pre-natal diagnosis (PND). This involves testing a fetus during pregnancy, to see whether it is likely to suffer from a number of different disorders — some genetic, some not. While recent developments allow tests for certain multifactorial genetic diseases (such as spina bifida), pre-natal diagnosis has been available since the 1960s to test for Down's syndrome.

Most cases of Down's syn
Author(s): The Open University

2.4 Current UK provision

One way of describing the organizational shift that the advent of predictive medicine would demand is to suggest that genetics would become a general, rather than a specialist service. But it is much easier to say that than to explain how it will happen. For all the publicity about genes, genomes and genetic information, medical genetics is a very small part of current health services.

In the UK, an indication that a patient or a family has a genetic problem will lead to a referral to a
Author(s): The Open University

2.3 Scaling up

They may look at dozens of alleles, and involve thousands of people, but existing screening programmes have been concerned with individual genes. But the technologies now being developed will soon permit the recording of hundreds of genes at a time. So-called gene chips combine the skills of microchip designers with DNA sequence information to offer rapid, easy-to-read results for an individual covering hundreds of genetic variants. A gene chip is a thin slice of glass about the
Author(s): The Open University

2.2.4 Longer-term considerations

Something else to ponder is the effect that screening might have on the longer-term incidence of disease and (not the same thing) on the incidence of gene variants linked to disease. Sometimes, the impact on a disease can be dramatic. Take thalassaemia, a haemoglobin disorder similar to sickle cell disease, in which premature destruction of haemoglobin-containing red blood cells leads to anaemia. It is relatively common in some Mediterranean countries. Like sickle cell disease, it is understo
Author(s): The Open University

2.2.3 Cystic fibrosis

A different model for the genetic tests of the future is screening for cystic fibrosis (CF). This is a DNA-based test, which became possible after the gene involved in CF was identified in 1989. CF is a recessive disease, and it should be easy to test to see if prospective parents carry a mutated allele. A simple mouthwash yields enough cells for DNA extraction. If both partners are carriers, they can consider further counselling before conception, and/or pre-natal testing of any potentially
Author(s): The Open University

2.2.1 Phenylketonuria

The classic example of population screening is testing new-born babies for phenylketonuria (PKU). Individuals with PKU fail to make a protein, a certain enzyme, and develop mental retardation. The absence of the enzyme results in both an accumulation of phenylalanine, which causes the mental retardation, and a deficiency of tyrosine in the body, as shown in Author(s): The Open University

2.2 Population screening for genetic disease: the precedents

Knowing about particular genes, or their effects, also permits screening – the search in a population for persons with certain genotypes that are associated with a particular disease. Thus the test may be offered to one and all. Until now, screening programmes have focused on one gene at a time, or one disease at a time, in cases where a mutated gene poses serious health problems and something can be done for those who are found to carry the mutation. What that something is varies with the
Author(s): The Open University

1.1 What is the future of healthcare?

When someone in the UK visits their GP for a flu jab, to confirm a pregnancy, or to report an unexpected pain, they know that behind him or her stands a vast system for diagnosis, treatment or prevention of disease in the whole population. The details differ from country to country but, like all industrialized countries, the UK has a healthcare system that is one of the largest industries. Tens of thousands of people and tens of billions of pounds a year come together inside a complicated net
Author(s): The Open University

Pizza Physics (New York-Style)
People love eating pizza, but every style of pie a has a different consistency. If "New York-style"--thin, flat, and large--is your texture of choice, then you've probably eaten a slice that was as messy as it was delicious. Colm Kelleher outlines the scientific and mathematical properties that make folding a slice the long way the best alternative...to wearing a bib.  (03:57)

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Cheery: The true adventures of a Chiricahua Frog

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