STS Lam

The commonest inherited metabolic disease in Hong Kong is glucose-6-phosphate dehydrogenase (G6PD) deficiency. When a disease is of significant incidence and severity, the public health approach would be considered for its prevention and management. In Hong Kong, G6PD deficiency was recognised as one such condition that required massive screening and early intervention. A combined neonatal screening programme for G6PD deficiency and congenital hypothyroidism (CHT) was started in Hong Kong by the Department of Health (DH) since 1984. The screening system included activities in public education, sampling, laboratory assays, follow up intervention and evaluation. As a public health programme, it was provided free of charge on a totally voluntary basis. Although all newborns in Hong Kong were entitled to this service, only about 70% of life birth had their blood samples directed to the central neonatal screening laboratory under this programme, the remaining 30% received screening from laboratories in private hospitals. Overall, more than 99% of all newborns in Hong Kong received screening for these disorders. Cord blood was used universally as the screening sample for both conditions. The decision of employing cord blood, instead of filter paper blood spot, was based on two reasons. Firstly, it was considered important that any deficiency of this enzyme in a newborn need be notified within the first couple of days for effective counselling and intervention. The use of cord blood certainly offered distinct advantage. Secondly, transport of these samples was not a problem in a geographically compact place like Hong Kong. Screening for G6PD enzyme activity was performed by colorimetric assay. Up to the end of December 2001, a total of 679,241 neonates had been screened in the public hospitals. It was found that 4.53% of the males and 0.32% of the females were affected. Compared with 1970s, there was a tremendous decrease in the morbidity and mortality resulting from hyper-bilirubinaemia due to G6PD deficiency. There are occasional cases of mishap as a result of failure to inform individual families of G6PD deficiency during the long holidays. Counselling for this condition was normally conducted by phone by genetic counselors, and this method had been shown to be effective.