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1、专家笔谈 Experience of medical genetics in Hong Kong Stephen TS LAM (Hong Kong Society of Medical Genetics, Hong Kong, China) KEY WORDS Genetics, medical; Genetic services; Hong kong As a geographically integral part of south China,the population mix of Hong Kong is largely influenced by its location. I
2、n the past 150 years,its population has increased from a few thousand to 5. 7 million. This is the result of episodic influxes of a great mass of people from China,often associated with political upheavals or economic cri- sis. It explains a population structure of 95% Chinese. This structure is als
3、o reflected in the finding of genetic vari- ants in this population,which bears resemblance to neighbouring regions in China. For example,the thalassaemias and lactose intolerance are common. However,the impact of migration from other parts of China cannot be neglec- ted,particulary for the last hal
4、f century. This is evident from studies of glucose-6-phosphate dehydrogenase (G6PD)variants and other protein polymorphisms. The quick change in political situation has also promoted more influx of people from central and northern part of China. They bring with them a diversity of genetic constituen
5、t, mutations and diseases. However, as an international city, Hong Kong has significant input from most ethnic groups in the world. Hence,the remaining 5% of its population is a heterogeneous group of minorities including Europe- ans,Indians,Japanese,and south-east Asians. Although their contributio
6、n to the cultural and economic growth in Hong Kong is phenomenal,their impact on the genetic load is small. However,since their genetic makeup,and hence diseases,vary somewhat from southern Chinese,they also poses specific needs to the provision of clinical ge- netic services. Before 1969,organized
7、activities in medical genetics in Hong Kong were minimal. The following decade wit- nessed a slow start in cytogenetics. After a period of training in Scandinavia Dr. Alice CHAU of Paediatrics Unit of University of Hong Kong introduced cytogenetics into their laboratory. Mr. LEE Fuk Tung was the lab
8、oratory super- intendent of this laboratory during that period. On the other side of the harbour at Queen Elizabeth Hospital a small amount of chromosome studies was performed at the Pathology Laboratory. Mr. CHAN Wing Kwong was the medical technologist specializing in this area. The karyotypes prod
9、uced then were non-banded orcein stained preparations. This was followed later by the formal establishment of a genetic counseling clinic in Queen Elizabeth Hospital in 1975. For the next five years,this clinic was conducted on a monthly basis. Chromosome studies(on orcein stained preparations)were
10、performed at the back bench of a paediatrics laboratory without the benefit of assistance from any technician. This was the modest start of a clinical genetic service in Hong Kong. Meanwhile, at the Paedi- atrics Unit of University of Hong Kong,Mr. LEE Fuk Tung,after a period of training in Glasgow
11、in cytogenetics, was establishing the first G-banded chromosome study laboratory in this locality. The author had the privilege of working in his laboratory to master this technique. Towards the end of this period, it was considered desirable to set up a formal clinical genetic service. Professor M
12、FERGUSON-SMITH from the University of Glasgow was invited in 1978 by the Medical Faculty of University of Hong Kong to recommend the establishment of a genetic department at the university. The terms of reference was “To advise the University of Hong Kong,in consultation with the Government Medical
13、and Health Department,on the accommodation,equipment and staffing which would be required to set up a cytogenetics service and genetic counseling clinic within the framework of the medical and health services in Hong Kong. ”In his report,he con- firmed that the demand for genetic services in Hong Ko
14、ng was not being met by the existing facilities. It was sugges- ted that a major reduction in the burden of genetic diseases on individual families and the community could be a- chieved by the provision of a comprehensive service. It was recommended that a comprehensive genetic service should be set
15、 up by establishing a central Medical Genetics Department. This department should be located adja- cent to a large teaching hospital and directed by a clinical geneticist with a University appointment. However,the recommendations in this report did not materialize. Subsequently,Professor PE POLANI f
16、rom London was invited by the Department of Medical and Health Serv- ices of Hong Kong(DMHS)to look into the feasibility of establishing a genetic service in Hong Kong,in the ab- sence of an existing Academic Department of Human and Medical Genetics. The first task that he did was to consid- er whet
17、her such a service was indeed required at that time in Hong Kong,and in the light of information and dis- cussion he concluded that it was needed. He pointed out that in all advanced communities genetic factors play an increasingly important role in disease and malformation. In addition,preventive a
18、ctions could be taken to lessen burden on individuals,family and the Society via genetic counseling,screening and prenatal diagnosis. He went on to propose a comprehensive scheme,defining in detail the structures of such a service,with its components of ge- netic counseling clinics,cytogenetic labor
19、atories,and neonatal screening programmes. It also dealt with the staffing Corresponding author s e-mail, ts-lam dh. gov. hk 71 北京大学学报 (医学版) JOURNAL OF PEKING UNIVERSITY (HEALTH SCIENCES) Vol.38 No. 1 Feb. 2006 of these services and training of personnel. He took note of the fact that Professor Ho K
20、ei MA was considering to de- velop prenatal diagnosis as part of the obstetric services in Tsan Yuk Hospital. As a start,he advised that the cyto genetic laboratory of the proposed Clinical Genetic Service would best be housed also in the Tsan Yuk Hospital. He considered it important to centralise o
21、n the same site the diagnostic facilities for cytogenetic service for the whole of Hong Kong. In addition,plans for screening of glucose-6-phosphated dehydrogenase deficiency,congenital hypot- hyroidism and thalassemia were discussed. The importance of research on genetic and part-genetic disease wa
22、s also emphasized. At the end of his report,he alluded to the importance of having an Academic Department of Human and Medical Genetics in Hong Kong. This plan was adopted by DMHS and has been followed faithfully in the past decade. As a start, clinicians and technologists were sent for in depth tra
23、ining to various genetic centers and labora- tories. Mr. CHAN Wing Kwong was sent for advanced cytogenetic training in Bristol and Miss Miranda YUEN at- tended the Guy s Hospital Paediatric Research Unit for biochemical genetics studies. The author also received training in the latter Unit for clini
24、cal and biochemical genetics. 1 Implementation In 1981 two separate services were set up to cater for needs of this population. At the Department of Obstetrics and Gynaecology of University of Hong Kong Professor Ho Kei MA had long envisaged the need for prenatal diagnos- tic service in Hong Kong. S
25、he saw to it that government funding and private donations were made available to estab- lish the prenatal diagnostic laboratory at the Tsan Yuk Hospital. It was named Mrs. WU Chung Prenatal Diagnostic Laboratory. Staffed by obstetricians and technologists with training in medical genetics,this unit
26、 quickly became the center of prenatal diagnostic services in Hong Kong. The other genetic service was set up by the Medical and Health Services Department according to the“blue- print”lay down by Professor Polani. It was named the Clinical Genetic Service of Hong Kong and was staffed by paediatrici
27、ans trained in clinical genetics and technologists trained in cytogenetics. During this initial phase,the CGS did not own a premise of its own. While the clinical component was housed in Queen Elizabeth Hospital,the cytogenetic laboratory was established on the ground floor of Tsan YuK Hospital. Hen
28、ce the two cytogenetics labora- tory(of CGS and PDC)were in close proximity which rendered much fruitful collaborations between the two units. In the following sections,only the work of CGS will be described. 2 Phase 1 of CGS The development of CGS could best be divided into two phases,which coincid
29、ed with the periods of adminis- trative jurisdiction of this service. The first phase covered the period of 1981 to 1990 during which time CGS was under the administration of M&HD. It was headed by Dr. Alice CHAU who was then the Consultant Paediatrician heading one of the two paediatric units in th
30、at hospital. The author was one of the assistants to Dr. CHAU. All cli- nicians in this team were working simultaneously as paediatricians and clinical geneticist,with different apportion- ment of time spent in either disciplines. The physical location of this service was split into two sites. While
31、 the cy- togenetic laboratory was housed in Tsan Yuk Hospital,the genetic counseling team of staff was stationed in Queen Elizabeth Hospital. Medical staff of this team had double appointments both in paediatrics and clinical genetics. These two units were responsible for a service which provided ge
32、netic consultation,diagnosis(both clinical and cy- togenetic)and counseling to the public. Patients and their families were referred from medical practitioners in ei- ther public or private sector. They were seen either at the clinics(at QEH or Sai Ying Pun Jockey Club Clinic to cover needs from bot
33、h sides of the Hong Kong harbour)or in public hospital wards in case of emergency. There was a steady increase in referral throughout this period as clinicians gradually came to realize the importance of this branch of medicine. A register was kept to document the referrals to this service(in this c
34、ontext,the term register refers to the collection biological and clinical data of patients and families which serve the purpose of indexing,an alternate use of this term will be outlined in further detail in a following section) . It was envisaged that,during this early phase of the development of t
35、his kind of service,a lot of promotional and educational work had to be performed. The main objective was to spread the message among healthcare profes- sionals,which would then sink through to the public. For this purpose,regular educational“Genetic Seminars” were organized in various hospitals on
36、a weekly basis. It was like a circus tour that would go round some of the ma- jor hospitals all year round,attracting audience from paediatrics,obstetrics and gynaecology and other specialties. These seminars were conducted in the Queen Elizabeth Hospital,Queen Mary Hospital,Princess Margaret Hospi-
37、 tal,Prince of Wales Hospital,and Tuen Mun Hospital. It was this incessant effort that helped to promote genetic knowledge among healthcare professionals,materializing,in turn,the importance of this kind of service. In 1984,an additional unit,named the Central Genetic Neonatal screening Unit,was est
38、ablished in CGS. This unit was responsible for running a territory wide programme for neonatal screening for G6PD deficiency and congenital hypothyroidism. Earlier studies had shown that these conditions were of significance among the local pop- ulation,and that criteria for screening and further ma
39、nagement had been met. A Steering Committee was set up at the M&HSD to study the feasibility and,subsequently,advised on the planning and implementation of such pro- gramme. This committee comprised of representatives from both academic and government sector. An important promotor of this service wa
40、s Dr. SH LEE(who was subsequently the first Director of Department of Health) . This 81 北京大学学报 (医学版) JOURNAL OF PEKING UNIVERSITY (HEALTH SCIENCES) Vol. 38 No. 1 Feb. 2006 approach of the application of genetic knowledge to whole at risk populations are also known as community genetic services,as co
41、ined by Bernadette Modell in 1990. From April 1984 to December 2004,a total of 802 464 newbo- rns were screened via this system,with 20 109 cases of G6PD deficiency detected and counseled,and 374 subjects with hypothyroidism treated. The incidence of G6PD deficiency was 4. 4% for males and 0. 37% fo
42、r females. That of congenital hypothyroidism was 1 in 2 146. 3 Phase 2 of CGS The early nineties witnessed some significant changes in the development of this service. Upon the establish- ment of Department of Health(DH)in 1989,it was considered pertinent for CGS to be grouped under this newly forme
43、d government department. The main rationale was that the kind of service provided by CGS was mainly for prevention of genetic diseases, and preventive approach to diseases fell under one of the main core functions of DH. In 1990,a Consultant Clinical Geneticist posts was established in this departme
44、nt,and the author was appointed to this capacity. CGS was formally separated from Paediatrics A Unit of Queen Elizabeth Hospital and became a u- nique service of its kind with a mandate of providing clinical genetic services to the public of Hong Kong on a terri- tory wide basis. Clinical staff of C
45、GS moved from its original location in QEH to the Clinical Genetic Service Center in Sham Shui Po,to join colleagues of the cytogenetic team who also moved there from the Tsan Yuk Hospital. This was the first time all members of CGS could actually work under the same roof on a daily basis. This arra
46、ngement helped to improve coordination among different components of this service. However,separation from the Tsan Yuk Hospital also meant less contact with colleagues in the PDC,who had been close partners in the eighties. Contacts with clinical units in the public hospitals did not decrease thoug
47、h,since patients were continuously referred to CGS either on urgent consultation basis or as outpatient genetic consults at the venues mentioned previously. Once established in its new“home” ,the cytogenetics laboratory started to proceed into a new phase. Molecu- lar cytogenetics was introduced int
48、o its armamentarium. This new technology, in situ hybridization, was first experi- mentally established in 1969,and was originally based on isotopic detection of signals arising from gene probes hy- bridized to specific sites on chromosomes. Development in the late eighties allowed hybridization sig
49、nals to be de- tected by fluorescence,hence the term FISH,which stands for fluorescence in situ hybridization. This technology was put to good use in our laboratory in the diagnosis of hundreds of patients suffering from various forms of chromo- some microdeletions,monogenic and other chromosome disorders. By 1995,this technology was firmly established in our laboratory. Of recent,the technique of multi-color FISH and studies of subtelomeric deletions were estab- lished in this laboratory. Overall,the cytogenetic laboratory had processed a total of 21 558 samples from 1981 to 2004.
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