We have characterised the genetic heterogeneity in channelopathies and cardiomyopathies among Hong Kong Chinese patients in a 10-year case series. Correct interpretation of genetic findings is difficult and requires expertise and experience. Caution regarding issues of non-penetrance, variable expressivity, phenotype-genotype correlation, susceptibility risk, and digenic inheritance is necessary for genetic counselling and cascade screening.

The numbers of immunoreactive gastrin and somatostatin cells in gastric and duodenal mucosal biopsy specimens from dyspeptic patients with duodenal ulcers and dyspeptic controls without ulcers were calculated using a morphometric method. The levels of gastrin and somatostatin in the tissue were also measured by the radioimmunoassay. The results showed no significant difference in the number of G cells and the level of gastrin in the tissue between the ulcer and non-ulcer groups. However, the number of D cells and the level of somatostatin in the tissue in ulcer patients were remarkably reduced in comparison with those in non-ulcer patients (P less than 0.01 and P less than 0.05, respectively). The G:D cells and gastrin:somatostatin ratios in ulcer patients were much higher than those in the non-ulcer control group. It is considered that the reduction of D cells and the relative lack of somatostatin in duodenal ulcer patients might have a role in the mechanism of the duodenal ulceration.