OBJECTIVETo test the frequency and pattern of rhodopsin (RHO) mutations in Chinese retinitis pigmentosa (RP) patients and to evaluate their effects in the pathogenesis of RP.

METHODSGenomic DNA was extracted from peripheral blood samples of 100 Hong Kong Chinese RP patients. Sequence variants of the entire coding exons of the RHO gene were tested using PCR, conformation sensitive gel electrophoresis and DNA sequencing.

RESULTSTotally six nucleotide changes were identified, among which three were silent mutations, two missense mutations and one deletion mutation. P347L was found in one RP proband and her three children who also had RP. P327(1 bp del) was novel and detected in a late-onset RP patient of 53 years. Her 26-year-old daughter, also carrying the identified mutation, had no RP phenotypes except for the mottled retinal pigment epithelium (RPE) revealed by fundal examination. Neither of the two mutations was detected in normal controls.

CONCLUSIONTwo patients had disease-causing mutations in the RHO gene, thus RHO mutations cause about 2.0% (95% confidence interval: 0.2%-7.0%) of all RP among Chinese in Hong Kong. A highly conserved C-terminal sequence QVS(A)PA was altered due to P347L and thereby resulting in an aberrant subcellular localization of rhodopsin. Loss of all six phosphorylatable residues at the C-terminus and the highly conserved C-terminal sequence QVS(A)PA may occur because of P327(1 bp del). To elucidate the predominant biochemical defects in such mutant, transgenic mice and transfected culture cells carrying P327(1 bp del) would be of greatest value.

Adolescent ; Adult ; Aged ; Child ; China ; DNA ; chemistry ; genetics ; DNA Mutational Analysis ; Female ; Gene Frequency ; Genetic Testing ; Humans ; Male ; Middle Aged ; Point Mutation ; Retinitis Pigmentosa ; genetics ; pathology ; prevention & control ; Rhodopsin ; genetics ; Sequence Deletion

OBJECTIVETo identify and evaluate mutations in the RP1 gene among Chinese patients with retinitis pigmentosa (RP).

METHODSLeukocyte DNA of 92 RP patients were collected in Hong Kong. Sequence changes of the entire coding region of the RP1 gene were examined using PCR, conformation sensitive gel electrophoresis and DNA sequencing.

RESULTSIn total, 1 nonsense mutation and 1 nonsense variant as well as 10 missense alterations were identified in the RP1 gene, among which, Arg677Ter was found in 1 RP patient and another nonsense variant, Arg1933Ter, was identified in 3 normal individuals and 1 patient with Stargardt's disease, suggesting its nonpathogenicity. Arg77Ter is expected to lead to large disruptions of the encoded protein.

CONCLUSIONSThe nonpathogenicity of Arg1933Ter indicates that the C-terminal 224 residues of RP1 protein may be not critical for RP1. The most C-terminal truncation previously reported was due to Tyr1053 (1-bp del) and occurred in RP patients. Thus RP can be caused by reduction in the level of the region of RP1 protein after codon 1052 but before 1933. To ascertain such a proposition, genotypes of more RP patients may reveal more RP causative mutations and more sequence alterations different than those of other ethnic groups.

Adolescent ; Adult ; Aged ; Child ; Codon, Nonsense ; DNA Mutational Analysis ; Eye Proteins ; genetics ; Female ; Humans ; Male ; Middle Aged ; Mutation, Missense ; Retinitis Pigmentosa ; genetics

OBJECTIVETo investigate the frequency and pattern of RP1 point mutations in Chinese retinitis pigmentosa (RP) patients and to examine their effects on the development of RP.

METHODSConformation sensitive gel electrophoresis (CSGE) and direct DNA sequencing were used to determine sequence alterations occurring in the entire coding region of the RP1 gene in 101 Chinese RP patients in Hong Kong.

RESULTSR677X was detected in one RP patient. A nonpathogenic nonsense mutation, R1933X, was identified in three normal individuals and one patient with Stargardt disease. The frequency of RP1 mutations among all RP patients in this study is 1/101. R677X is expected to lead to large disruptions of the encoded protein. Additionally, 10 more missense alterations in the RP1 gene were identified in the subjects of this study. Apart from M479I whose pathogenicity can not be determined currently, other sequence changes are just polymorphisms of the RP1 gene.

CONCLUSIONThe nonpathogenicity of R1933X indicates that the C-terminal 224 residues of RP1 protein may be not critical for RP1. Recently, a C-termnal truncating mutation, Y1053(1 bp del), was reported to occur in an RP patient. Thus RP can be caused by lack of the region of RP1 protein after codon 1052 but before 1933. To confirm such a proposition, a large genotyping study is necessary and is likely to reveal more RP causative mutations and uncover more sequence alterations different from those of other ethnic groups.

Adolescent ; Adult ; Aged ; Child ; China ; DNA ; chemistry ; genetics ; DNA Mutational Analysis ; Eye Proteins ; genetics ; Female ; Gene Frequency ; Genotype ; Humans ; Male ; Middle Aged ; Mutation ; Mutation, Missense ; Retinitis Pigmentosa ; genetics

Apoptosis ; Extracellular Matrix Proteins ; metabolism ; Glaucoma ; pathology ; Glutamic Acid ; metabolism ; Humans ; Neuroglia ; pathology ; physiology ; Nitric Oxide Synthase ; physiology ; Optic Nerve ; physiology ; Optic Nerve Diseases ; pathology ; Retinal Ganglion Cells ; pathology ; Tumor Necrosis Factor-alpha ; physiology

BACKGROUNDPrimary open-angle glaucoma (POAG) is characterized by optic nerve damage and consists of a group of genetically heterogeneous disorders. This study was to investigate the associations of genetic and environmental factors with POAG in a hospital-based Chinese population.

METHODSThirty-two adult onset POAG patients and 96 age-sex matched control subjects were studied by multivariable logistic regression analysis for the relationships between POAG and its risk factors including family history, diabetes, hypertension, cardiovascular diseases, cigarette smoking, alcohol consumption and polymorphisms of the myocilin and the optineurin genes.

RESULTSUnivariate analysis showed that POAG was related to family history, cardiovascular disease, alcohol consumption and a myocilin sequence alteration (T353I) (P < 0.04). Multivariable logistic regression analysis confirmed that POAG was significantly associated with family history (OR = 20.2), hypertension (OR = 3.58), cigarette smoking (OR = 10.8), alcohol consumption (OR = 0.028) and T353I (OR = 6.03, all P < 0.05).

CONCLUSIONSFamily history, hypertension, cigarette smoking and T353I in the myocilin gene are risk factors for POAG. Alcohol consumption, however, has a protective effect.

Adult ; Aged ; Aged, 80 and over ; Alcohol Drinking ; adverse effects ; Cytoskeletal Proteins ; Eye Proteins ; genetics ; Female ; Glaucoma, Open-Angle ; etiology ; genetics ; Glycoproteins ; genetics ; Humans ; Hypertension ; complications ; Logistic Models ; Male ; Middle Aged ; Risk Factors ; Smoking ; adverse effects

OBJECTIVETo investigate the role of lipoprotein lipase (LPL) gene on Chinese patients with hypertriglyceridemic type 2 diabetes.

METHODSThree subject groups, including hypertriglyceridemic group, normalipidemic type 2 diabetes group and healthy controls, were recruited and screened for sequence changes in LPL gene with PCR, SSCP, restriction analysis and direct DNA sequencing. LPL mass and activity in post-heparin plasma and in in vitro expression were investigated. Comparative modeling was performed via Swiss-PDB Viewer to provide the potential 2-D structures of wildtype and mutant proteins.

RESULTSFour missense mutations, Ala71Thr, Val18Ile, Gly188Glu and Glu242Lys, were identified in patients with hypertriglyceridemic type 2 diabetes, and not in both normalipidemic diabetes and the control subjects. The four missense mutations were located in the highly conserved amino acid sites, which are involved in highly conserved exon 3, 5, or 6 regions. They led to reduced LPL mass and enzyme activities in both post-heparin plasma and in vitro expression. The modeled structures displayed the differences to a great extent between the mutant and wide-type molecules.

CONCLUSIONThese results indicated that the 4 missense mutations lead to LPL deficiency and subsequent hypertriglyceridemia. The LPL deficiency predispose a progressive diabetic pathway to those affected individuals. LPL gene is one of susceptibility gene for hypertriglyceridemic type 2 diabetes.

Asian Continental Ancestry Group ; Diabetes Mellitus, Type 2 ; complications ; genetics ; Female ; Genetic Predisposition to Disease ; Humans ; Hypertriglyceridemia ; complications ; enzymology ; genetics ; Lipoprotein Lipase ; genetics ; Male ; Middle Aged ; Mutation, Missense ; Polymerase Chain Reaction ; Polymorphism, Single-Stranded Conformational

OBJECTIVETo detect single nucleotide polymorphisms (SNPs) of the myocilin (MYOC) gene and to investigate their associations with primary open-angle glaucoma (POAG).

METHODSOne hundred and fifty-seven sporadic patients with POAG and 155 unrelated control subjects without POAG were recruited from staff and visitors to the Prince of Wales Hospital between 1998 and 2000. All study subjects are ethnic Chinese living in Hong Kong. The two populations were matched in frequencies of gender and age. The SNPs of the MYOC gene in POAG patients and control subjects were screened and identified by high throughout conformation sensitive gel electrophoresis and fluorescent labeling automated sequencing. The genotype frequencies of each SNP in the two groups were compared by the Chi2 test or Fisher's exact 2-tailed test.

RESULTSA total of seventeen SNPs were identified from 2172 bp long of the MYOC gene, including all 3 exons and adjacent non-coding regions. The identified SNPs were 1-83G --> A, G12R, P16L, A17S, R46X, R76K, R91X, T123T, D208E, L215P, 730+35A --> G, A260A, I288I, E300K, T353I, Y471C and 1515+73G --> C, respectively. Of these, R91X, E300K and Y471C were found only in POAG patients. A significant difference between POAG patients and control subjects was found in the genotype frequencies of 1515+73G --> C. The frequency of the heterozygote (CG) was 0.6% in POAG patients, significantly less than the 4.5% in control subjects (Fisher's exact 2-tailed test, P=0.036, OR=0.136, 95%CI=0.022-0.828). No significant difference was found between the two populations in genotype frequencies of all other SNPs.

CONCLUSIONThe polymorphisms of the MYOC gene may be related to POAG.

Adult ; Aged ; Aged, 80 and over ; Amino Acid Substitution ; Base Sequence ; Case-Control Studies ; Cytoskeletal Proteins ; DNA ; chemistry ; genetics ; DNA Mutational Analysis ; Eye Proteins ; genetics ; Female ; Gene Frequency ; Genotype ; Glaucoma, Open-Angle ; genetics ; pathology ; Glycoproteins ; genetics ; Humans ; Male ; Middle Aged ; Point Mutation ; Polymorphism, Single Nucleotide

OBJECTIVETo investigate the efficacy of a herbal formula in the prevention of influenza or influenza-like syndrome among elderies residing in old-people's home in Hong Kong. The secondary objectives are to investigate the quality of life (QOL) and symptomology changes among the herbal users and to evaluate the safety of this formula.

METHODSIn ten old people's home or community centres in New Territories, Hong Kong, 740 eligible subjects agreed to join the study and were randomized to receive a herbal formula or a placebo on alternate days over 8 weeks. Among those 740 participants, 113 had provided blood samples for immunological assessments before and after the study drug. Assessments were done at 0, 4, 8 and 12 weeks. Participants were instructed to keep a daily record of body temperature and any symptoms as sore throat, myalgia, running nose or cough, and to report to assessor accordingly. Those reporting body temperature of 37.8 °C and above would be visited and a proper nasopharyngeal swab be taken for viral study.

RESULTSSeventy-two participants developed influenza-like-symptoms but none of them was proven influenza in their nasopharyngeal swabs, 40 of these patients belonged to the herbal group and 32 to the placebo group, without significant differences between groups. The difference on the changes in QOL between the two groups was not statistically significant. However, in the immunological study, the natural killer cell absolute count was significantly increased in the herbal group compared with the placebo group (463 ± 253 vs 413 ± 198, P<0.05).

CONCLUSIONSThe herbal preparation was not effective compared with placebo in the prevention of influenza-like syndrome. It was however safe and possibly supporting immunological responses.

Aged ; Demography ; Double-Blind Method ; Drugs, Chinese Herbal ; adverse effects ; therapeutic use ; Female ; Humans ; Immunologic Tests ; Influenza, Human ; drug therapy ; immunology ; prevention & control ; Male ; Quality of Life ; Vaccination