The improved life expectancy of people with Down's syndrome as a result of the greater availability of surgery and advances in medical care has been widely documented. However, there has been no evaluation of survival in the Australian Down's syndrome population since the 1980s. This study aimed to evaluate the changes in survival from birth in cases of Down's syndrome notified to the Birth Defects Registry in Western Australia. Babies born with Down's syndrome between 1980 and 1996 (inclusive) and registered with the Birth Defects Registry were studied. Survival status was obtained in several ways. Cases were stratified into three cohorts for comparison. Survival curves were constructed using the methods of Kaplan and Meier. For infants born during 1980-96, survival to 1 year is now > 91%, and 85% can expect to survive until the age of 10 years. Although survival in those with heart disease showed improvement over the period studied, overall this was still a strong predictor of mortality. Survival in Aboriginal children with Down's syndrome was significantly poorer than in non-Aboriginal children, mirroring the pattern in the general population. Mortality was greater in females and in those with a low birthweight. There was no statistically significant difference in the survival between those born in metropolitan and in rural areas. There has been a considerable improvement in survival of infants born with Down's syndrome in Western Australia. This improvement is similar to findings in recent international studies. The difference in survival between Aboriginal and non-Aboriginal children is particularly disturbing. These findings are useful for both clinicians and families who need to plan for the long-term care of these children.

Background: Mutations in the MECP2 gene have been recently identified as the cause of Rett syndrome, prompting research into genotype-phenotype relations. However, despite these genetic advances there has been little descriptive epidemiology of the full range of phenotypes. Aims: To describe the variation in phenotype in Rett syndrome using four different scales, by means of a population database. Methods: Using multiple sources of ascertainment including the Australian Paediatric Surveillance Unit, the development of an Australian cohort of Rett syndrome cases born since 1976 has provided the first genetically characterised population based study of Rett syndrome. Follow up questionnaires were administered in 2000 to families and used to provide responses for items in four different severity scales. Results: A total of 199 verified cases of Rett syndrome were reported between January 1993 and July 2000; 152 families provided information for the follow up study. The mean score using the Kerr scale was 22.9 (SD 4.8) and ranged from 20.5 in those under 7 years to 24.2 in those over 17 years. The mean Percy score was 24.9 (SD 6.6) and also increased with age group from 23.0 to 26.9. The mean Pineda score was 16.3 (SD 4.5) and did not differ by age group. The mean WeeFIM was 29.0 (SD 11.9), indicating extreme dependence, and ranged from 18 to 75. Conclusion: We have expanded on the descriptive epidemiology of Rett syndrome and shown different patterns according to the severity scale selected. Although all affected children are severely functionally dependent, it is still possible to identify some variation in ability, even in children with identified MECP2 mutations.

We found that severe functional limitations are rare in school-aged children with Down syndrome. Some support and supervision are required for complex self-care, communication and social skill tasks. This study demonstrates the feasibility of using the WeeFIM for collecting population survey data in children with developmental disability. This may be useful for the longitudinal tracking of such populations, as well as the monitoring of response to interventions.

This study compares bone mass in a national sample of girls with Rett syndrome (RS) with a sample of control children. The Australian RS Database was the source of cases for this population-based study. Hand radiographs were available from 101 of 137 subjects (74% of the known Australian population of girls with RS aged < or = 20 years). Control radiographs matched for age, sex, and laterality were obtained from hospital radiology departments. A measure of cortical thickness was made from the difference between the outer diameter and the medullary space in the second metacarpal bone. A mean z-score value for cortical thickness and percentage cortical area for each individual was calculated. The mean cortical thickness (z score) for girls with RS was -1.94 compared with -0.38 for control children (P<0.001). In girls with RS, the mean cortical thickness decreased with age (P<0.001). In girls who were taking epilepsy medication it was -2.21 compared with -1.23 in those not taking epilepsy medication (P<0.001). There was no evidence of a beneficial effect of increased calcium intake on cortical thickness. A similar pattern was obtained when percentage cortical area was estimated. In multivariate analysis, increasing age and use of anticonvulsant medication were associated with decreased cortical thickness and only use of anticonvulsant medication with decreased percentage cortical area. Fractures had occurred in one-third of cases and it was estimated that just over 40% of girls would sustain a fracture by the age of 15 years. Girls with RS may be at increased risk of fractures and their bone quality compromised as determined by cortical thickness and percentage cortical area measurements from the second metacarpal.