OBJECTIVE. To review the outcome of unrelated umbilical cord blood transplantation in children using cord blood from the Hong Kong Red Cross Blood Transfusion Service.

DESIGN. Retrospective study.

PATIENTS. Records of eight patients who received unrelated umbilical cord blood transplants between 1999 and 2003 were reviewed.

MAIN OUTCOME MEASURES. Engraftment of haematopoietic cells and graft-versus-host disease after transplantation.

RESULTS. The median age of the patients was 4.9 years (range, 1.0-9.4 years). Five patients had acute leukaemia, one had non-Hodgkin's lymphoma, one had X-linked adrenoleukodystrophy, and one had mucolipidosis. The infused umbilical cord blood units contained a median of 6.7 x 10 ⁷ /kg nucleated cells and 4.0 x 10 /kg CD34-positive cells. Neutrophil engraftment was achieved at a median of 13 days (range, 11-19 days) and, for seven patients, platelet engraftment was achieved at a median of 39 days (range, 24-98 days). Acute graft-versus-host disease occurred in all patients (grades I to III). One of the patients died because of encephalitis; of the other seven, five developed chronic graft-versus-host disease of the skin. At a median follow-up of 2 years, the four patients with leukaemia and the one with non-Hodgkin's lymphoma remained in continuous complete remission; the patient with adrenoleukodystrophy showed stabilisation of neurological condition.

CONCLUSION. The Hong Kong Red Cross Blood Transfusion Service Cord Blood Bank stored cord blood units of good quality for transplantation, the outcome of which was comparable to that of bone marrow transplantation.

Key words: Child; Cord blood stem cell transplantation; Graft vs host disease; Leukemia

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OBJECTIVE. To present an institution's 2-year experience of non-myeloablative allogeneic stem cell transplantation among Chinese patients.

DESIGN. Retrospective study.

SETTING. Bone marrow transplantation unit at a university hospital, Hong Kong.

PATIENTS. Ten patients with multiple myeloma who received non-myeloablative allogeneic stem cell transplantation between March 2000 and October 2002.

INTERVENTION. Fludarabine (90 mg/m² ) and total body irradiation (300 cGy) were given as conditioning regimens, followed by non-myeloablative allogeneic stem cell transplantation.

MAIN OUTCOME MEASURES. Engraftment, regimen-related toxicity, treatment-related mortality (in the first 100 days), incidence of graft-versus-host disease, chimerism, disease response, and survival rate.

RESULTS. All 10 patients had active disease before transplantation. The donors were eight human leukocyte antigen-matched siblings, a mismatched sibling, and a matched daughter. Satisfactory engraftment before day 21 was achieved without early treatment-related mortality. Five patients developed full donor chimerism by day 28 and three other patients had 100% donor chimerism by day 100. Acute graft-versus-host disease developed in six patients (five with grade III and one with grade IV disease), and chronic graft-versus-host disease developed in eight patients (four with extensive disease). Complete remission and partial response were achieved in three and four patients, respectively. Three patients did not respond to treatment, and one case of relapse was observed. Only one patient, who had shown a partial response, received donor lymphocyte infusion; seven patients received thalidomide for graft-versus-host disease with or without graft-versus-myeloma effect. All patients were alive after a median follow-up of 1 year.

CONCLUSION. Non-myeloablative allogeneic stem cell transplantation for multiple myeloma is effective, has low toxicity, and results in low treatment-related mortality. Studies of more cases with longer follow-up durations are required.

Key words: Multiple myeloma; Myeloablative agents; Transplantation

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OBJECTIVE. To study the clinical profile and genetic basis of Brugada syndrome in Chinese patients.

DESIGN. Prospective observational study.

SETTING. Seven regional public hospitals, Hong Kong.

MAIN OUTCOME MEASURES. The clinical and follow-up data of 50 patients (47 men, 3 women; mean age, 53 years) were collected, and genetic data of 36 probands and eight family members of three genotyped probands were analysed.

RESULTS. Eight patients survived sudden cardiac death (group A), 12 had syncope of unknown origin but no sudden death (group B), and 30 were asymptomatic before recognition of Brugada syndrome (group C). Programmed electrical stimulation induced sustained ventricular arrhythmias in 88% (7/8), 82% (9/11), and 27% (3/11) of patients in group A, group B, and group C, respectively. New arrhythmic events occurred in 50% (4/8) of patients in group A and 17% (2/12) of patients in group B after a mean follow-up period of 30 (standard deviation, 13) months and 25 (7) months, respectively. All group C patients remained asymptomatic during a mean follow-up period of 25 (standard deviation, 11) months. Five of 36 probands and three of eight family members who underwent genetic testing were found to have a mutation in their SCN5A gene.

CONCLUSIONS. Chinese patients with Brugada syndrome who are symptomatic have a high likelihood of arrhythmia recurrence, whereas asymptomatic patients enjoy a good short-term prognosis. The prevalence of SCN5A mutation among probands is 14%. Thus, Chinese patients with Brugada syndrome share with their western counterparts similar clinical and genetic heterogeneity.

Key words: Arrhythmia; Chinese; Death, sudden, cardiac; Genetics; Recurrence

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OBJECTIVE. To estimate the incidence and document the clinical characteristics of Williams-Beuren syndrome in the Hong Kong Chinese population.

DESIGN. Cytogenetic analysis and retrospective study.

SETTING. Clinical Genetic Service, Department of Health, Hong Kong.

PATIENTS. Forty-one Chinese patients with Williams-Beuren syndrome.

MAIN OUTCOME MEASURES. From 1 January 1995 to 30 June 2002, fluorescence in situ hybridisation was used to confirm diagnoses in 41 cases of Williams-Beuren syndrome by detecting chromosome 7q microdeletion. Case records were reviewed, the incidence of the condition in the local population was estimated, and the main clinical characteristics were determined.

RESULTS. The minimal incidence of Williams-Beuren syndrome in this locality was estimated to be approximately 1 per 23 500 live births. Common dysmorphic facial features included periorbital fullness (83%), full lips (80%), a long philtrum (51%), a flat nasal bridge (41%), and abnormal teeth (37%). No patients had a stellate iris. The majority (82%) had at least one documented cardiac anomaly; among these patients, peripheral pulmonary stenosis was diagnosed in 61% and supravalvular aortic stenosis in 45%. Nearly all (93%) of the study group exhibited developmental delay.

CONCLUSION. As in the West, patients with Williams-Beuren syndrome in the Hong Kong Chinese population display craniofacial dysmorphism, cardiovascular anomalies, and mental deficiency. Supravalvular aortic stenosis—the cardiac defect most commonly associated with Williams-Beuren syndrome in western countries—is less common than peripheral pulmonary stenosis in this region.Studies involving periodic cardiovascular evaluation are needed to confirm if this difference is significant.

Key words: Abnormalities, multiple; Genetic disease, inborn; Williams syndrome

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OBJECTIVE. To assess the feasibility of implementing a universal neonatal hearing screening programme using distortion product otoacoustic emission detection at a major teaching hospital in Hong Kong.

DESIGN. Descriptive study and questionnaire.

SETTING. Teaching hospital, Hong Kong.

METHODS. A total of 1064 infants, together with their mothers, were successfully recruited for the study. The participation rate was 99.3%. A three-stage hearing screening protocol using distortion product otoacoustic emission detection was adopted. Each of the participating infants was screened on three separate occasions (day 1-4, day 5-14, and day 21-30 after birth), irrespective of the test results. A questionnaire was administered to 364 randomly selected mothers to determine whether as consumers of the hearing screening service, mothers would find screening desirable.

RESULTS. Results of the screening demonstrated an incidence of permanent bilateral hearing loss (≥40 dB in the better ear) of 0.28%. The results also showed that 3.5% of the screened infants were referred for subsequent diagnostic audiological assessment, including those suspected with unilateral as well as bilateral hearing loss. Data obtained were comparable to other reported results obtained using multi-stage screening protocols. Taking b oth the false positive rate and the default rate into consideration, the most appropriate time for screening in this hospital setting appeared to be around day 5 to 14 when infants returned to the hospital’s day centre as out-patients for routine medical follow-up. Since this day centre service is not generally provided by all maternity hospitals in Hong Kong, an alternative time for screening would be around day 21 to 30 when infants could return as out-patients solely for the hearing test. The results of the questionnaire suggested that most mothers thought a neonatal hearing screening would be desirable (91.35%). The majority (81.70%) indicated a preference for screening either within a few days of birth at the maternity ward prior to discharge from the hospital, or between 5 and 30 days when returning to the hospital as an outpatient.

CONCLUSION. It was concluded that a universal neonatal hearing screening programme could be readily implemented in a maternity hospital setting in Hong Kong.

Key words: Feasibility studies; Hearing tests; Infant, newborn; Neonatal screening

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