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Thirty-eight mutations and seven polymorphisms have recently been reported in the genes underlying the neuronal ceroid lipofuscinoses (NCLs) including 11 new mutations described here. A total of 114 mutations and 28 polymorphisms have now been described in the five human genes identified which cause NCL. Thirty-eight mutations are recorded for CLN1/PPT; 40 for CLN2/TTP-1, 31 for CLN3, four for CLN5, one for CLN8. Two mutations have been described in animal genes (cln8/mnd, CTSD). All mutations in NCL genes are contained in the NCL Mutation Database (http://www.ucl.ac.uk/NCL).

The polymerase chain reaction (PCR) is firmly established as the method of choice for DNA amplification, though alternative strategies, such as the ligase chain reaction, may also be employed. Despite the continued development of PCR applications for gene mapping and diagnostics, few revolutionary improvements have been made to the technique. The major exception is long-accurate PCR, which has increased the length of amplifiable DNA by an order of magnitude.

A cohort was established in 1981 of all 7317 white male employees in the amosite and crocidolite mines in South Africa whose names had appeared in the personnel records (initiated between 1945 and 1955) of the major companies. Some of the men had been employed as early as 1925, but only 8% had had more than 10 years of service. Three subcohorts were defined: 3212 men whose only exposure to asbestos was to amosite; 3430 exposed to crocidolite; and 675 to both amphiboles. No deaths or losses to view occurred before 1946, and 5925 men (81%) were known to be alive at the end of 1980. Losses to view numbered 167 (2%), and there had been 1225 deaths (17%), an excess of 331 over the number of deaths expected on the basis of the mortality of all white South African males. The fibre related excesses were of mesothelioma, lung cancer, and other respiratory diseases, but there were other excesses perhaps mainly related to socioeconomic factors including lifestyle. When cause of death was determined according to "best evidence" (after study of clinical, radiological, biopsy, and necropsy reports in conjunction with the death certificate), there were 30 deaths due to mesothelioma (22 pleural, six peritoneal, two other) and 65 due to cancer of trachea, bronchus, and lung. Various analyses of these deaths showed that crocidolite had higher toxicity than amosite for lung cancer and this was most pronounced for mesothelioma; there can now be no question that crocidolite is far more dangerous than amosite at least in so far as mesothelioma is concerned. Nevertheless, crocidolite induced mesothelioma appeared only in men who had been exposed for long periods, at least 12 months, but on average about 15 years.

Many of the statistics given in this report are estimates based on tentative data and on that extent are not reliable in a strict sense. But the picture they present of gross differences in demographic and social characteristics, in vital statistics, and in resources of medical manpower and hospital beds between major areas of the world is real. More than half of the people of the world live in South Asia and East Asia; population density is highest in Western Europe; and highest rates of population growth are in Middle America and Tropical South America. In Europe less than one-third of the population are aged under 20 years, whereas more than half the population are aged under 20 im Middle and Tropical South America and the Carribbean, in Africa and in South Asia. Urbanization is high in Temperate South America, Northern America, Northern and Western Europe, and Oceania. The daily dietary energy supply per person is 50% higher in Northern America, Europe, USSR, and Ocenia than in Africa (excluding Southern Africa, South and East Asia. The Gross National Product in Northern America is 10 times higher than in Tropical South America and 30 to 40 times higher than in Western Middle and Eastern Africa and in Middle South and South East Asia. Crude birth rates are close to three times higher in Africa, Middle America and South Asia than in Europe, North America and USSR. Differences in crude death rates are less--rates in Western, Middle and Eastern Africa are double these of America Europe, USSR and Oceania. The Expectation of Life is over 70 years for Northern America, Europe, USSR and Oceania. It is under 50 years for Western, Middle and Eastern Africa. In all areas the expectation of life at birth has increased--by up to 10 years--in the past quarter century. Infant mortality is less than 20 per 1 000 in Northern and Western Europe and Northern America. It is over 100 in Africa and South Asia. Number of physicians range from 25 per 10 000 population in USSR to less than 1 per 10 000 in Western, Middle and Eastern Africa. There are over 100 hospital beds per 10 000 population in USSR and in Northern and Western Europe, less than 10 per 10 000 in Western Africa, Middle South Asia and South East Asia.