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Citrin deficiency is one of the most common inborn errors of metabolism in East Asians, which may manifest as neonatal cholestasis, failure to thrive and dyslipidaemia, or recurrent hyperammonaemic encephalopathy. Its molecular diagnosis requires confirmation of the presence of biallelic pathogenic variants in SLC25A13 gene by sequencing, and analysis for a common insertion IVS16ins3kb. However, patients with compatible biochemical features but only one monoallelic pathogenic variant have remained a diagnostic challenge. Here we report the development, validation and application of a multiplex ligation-dependent probe amplification (MLPA) assay using an in-house oligonucleotide probemix and a customised Coffalyer.NET worksheet for detection of exonic copy number variations in SLC25A13. With this MLPA assay, we successfully identified the presence of a heterozygous exonic deletion in SLC25A13 in three of 15 (20%) unrelated individuals with only one monoallelic pathogenic variant detected using conventional methods. Three exonic deletions, two novel involving exon 14 and one reported involving exon 5, were subsequently confirmed with Sanger sequencing. In summary, we developed, evaluated, and demonstrated the clinical utility of an in-house MLPA assay to look for exonic deletions in SLC25A13 in patients with citrin deficiency. With the discovery of novel deletions, MLPA should be considered a test of choice for molecular diagnosis of citrin deficiency when the sequencing result is inconclusive.

Familial hCG syndrome is a rare and benign cause of elevated serum beta human chorionic gonadotropin (hCG). We present here a case of familial hCG syndrome diagnosed in a Hong Kong Chinese family, which we believe to be the first reported in Chinese. A 38-year-old woman presented with incidental finding of persistently elevated hCG, analytically confirmed both in urine and blood. Extensive radiological and biochemical work-up were performed but were negative for pregnancy and malignancy. Testing of another asymptomatic family member revealed unexplained elevation of serum hCG, confirming the diagnosis of familial hCG syndrome. Knowledge and awareness of this entity among clinicians are important to avoid unnecessary investigations and treatment in affected families.

Isolated 17,20-lyase deficiency may be caused by mutations in the CYP17A1 (coding for cytochrome P450c17), POR (coding for cytochrome P450 oxidoreductase) and CYB5A (coding for microsomal cytochrome b5) genes. Of these, mutations in the CYB5A gene have thus far only been described in genetic males who presented with methemoglobinemia and 46,XY disorders of sex development (DSD) due to 17,20-lyase deficiency. A 24-year-old Chinese woman presented to the hematology outpatient clinic with purplish discoloration of fingers, toes, and lips since childhood. Investigations confirmed methemoglobinemia. A homozygous c.105C>G (p.Tyr35Ter) nonsense mutation was detected in the CYB5A gene. Hormonal studies showed isolated 17,20-lyase deficiency. Interestingly, she had a completely normal female phenotype with no DSD, normal pubertal development, and spontaneous pregnancy giving birth uneventfully to a healthy female infant. The sex hormone-related features of genetic females with 17,20-lyase deficiency due to cytochrome b5 gene mutation appear to differ from that of females with 17,20-lyase deficiency caused by other genetic defects who presented with hypergonadotropic hypogonadism and infertility and differ from genetic males with the same mutation.

Introduction Newborn screening is important for early diagnosis and effective treatment of inborn errors of metabolism (IEM). In response to a 2008 coroners' report of a 14-year-old boy who died of an undiagnosed IEM, the OPathPaed service model was proposed. In the present study, we investigated the feasibility of the OPathPaed model for delivering expanded newborn screening in Hong Kong. In addition, health care professionals were surveyed on their knowledge and opinions of newborn screening for IEM. Methods The present prospective study involving three regional hospitals was conducted in phases, from 1 October 2012 to 31 August 2014. The 10 steps of the OPathPaed model were evaluated: parental education, consent, sampling, sample dispatch, dried blood spot preparation and testing, reporting, recall and counselling, confirmation test, treatment and monitoring, and cost-benefit analysis. A fully automated online extraction system for dried blood spot analysis was also evaluated. A questionnaire was distributed to 430 health care professionals by convenience sampling. Results In total, 2440 neonates were recruited for newborn screening; no true-positive cases were found. Completed questionnaires were received from 210 respondents. Health care professionals supported implementation of an expanded newborn screening for IEM. In addition, there is a substantial need of more education for health care professionals. The majority of respondents supported implementing the expanded newborn screening for IEM immediately or within 3 years. Conclusion The feasibility of OPathPaed model has been confirmed. It is significant and timely that when this pilot study was completed, a government-led initiative to study the feasibility of newborn screening for IEM in the public health care system on a larger scale was announced in the Hong Kong Special Administrative Region Chief Executive Policy Address of 2015.

Introduction There is a pressing need to identify diagnostic testing for Cushing's syndrome that can be achieved with ease and at low cost. This study aimed to explore the usefulness of late-night and post-overnight 1-mg dexamethasone suppression salivary cortisone, as measured by liquid chromatography-tandem mass spectrometry, for investigation of hypercortisolism. Methods Salivary cortisone data of subjects were investigated according to a pre-specified protocol. Subjects were classified as having 'hypercortisolism' or 'eucortisolism' on the basis of histological or biochemical criteria. Receiver operating characteristic curves were drawn to identify the cut-off values and study their performance characteristics. We measured 24-hour urinary free cortisol; late-night salivary cortisol and cortisone; and post-overnight 1-mg dexamethasone suppression serum cortisol, and salivary cortisol and cortisone. Saliva and urine samples were assayed by liquid chromatography-tandem mass spectrometry. Results In this study, 21 subjects were classified as having hypercortisolism and 78 as having eucortisolism. A late-night salivary cortisone cut-off of 13.50 nmol/L had a sensitivity of 94.7% and a specificity of 87.2%. After taking 1-mg dexamethasone the night before, a salivary cortisol cut-off of 0.85 nmol/L had a sensitivity of 76.2% and a specificity of 96.2%; a salivary cortisone cut-off of 7.45 nmol/L had a sensitivity of 85.7% and a specificity of 94.9%, while a salivary cortisone cut-off of 3.25 nmol/L had a sensitivity of 95.2% and a specificity of 79.5%. Many salivary cortisol samples were below the detection limit of liquid chromatography-tandem mass spectrometry. In comparison with salivary cortisol, salivary cortisone had a better correlation with total serum cortisol and better diagnostic performance following dexamethasone suppression. Conclusions Both late-night and post-overnight dexamethasone suppression salivary cortisone levels are of diagnostic value in the investigation of hypercortisolism.

Glycogen storage disease type la (GSD1a) is an autosomal recessive metabolic disorder caused by a deficiency in glucose-6-phosphatase (G6Pase). We analyzed the G6Pase genes of two unrelated Chinese families with GSD1a. DNA sequencing of all five exons and the exon-intron boundaries revealed a G T transversion at nucleotide 727 (727G-->T) in exon 5, which has previously been reported to cause abnormal splicing. In one family, the subject and her affected sister were confirmed to be homozygous for this mutation and their parents to be heterozygotes. In the other family, the proband was identified to be heterozygous for this mutation, and a novel mutation, the 341delG in exon 2, was identified. This mutation alters the reading frame and creates a stop codon TAA 15 codons downstream from the mutation, resulting in a truncated protein. Family studies revealed that the father was heterozygous for the 727G-->T mutation and that the mother was heterozygous for the 341delG mutation. This is the first time that the 727G T mutation has been found in Chinese patients or outside Japan. Since we only tested two GSD1a families and found 727G-->T in both, we believe that this mutation may also be prevalent in our local Chinese population. To investigate allele frequencies, we screened 385 Chinese healthy volunteers and found two asymptomatic carriers. Our findings suggest that the 727G-->T mutation is indeed prevalent in Hong Kong.

Aim: Setting up reference intervals from the local service populations is one of the major responsibilities of clinical laboratories. Yet, this task is difficult to achieve because it is costly and time consuming when compared with validating reference intervals from assay manufacturers. Methods: Following the recommendations of the International Federation of Clinical Chemistry, healthy local Chinese adults were recruited to set up reference intervals for common serum analytes. Statistical methods recommended by the National Committee for Clinical Laboratory Standards were used for defining the reference limits. Results: Data from 335 subjects were analysed. The reference intervals set up were broadly similar to those provided by the assay manufacturer, except for sodium and potassium. Glomerular filtration rate was estimated by the modification of diet in renal disease equation, with or without modification for Chinese. Body mass index had a significant impact on serum urate and alanine aminotransferase levels. Conclusion: Reference intervals of common serum analytes have been set up for the local Chinese population. A good example of quality laboratory service has also been set up to provide clinicians with reliable reference intervals that they can confidently rely on for the diagnosis and management of patients.

Objective Disorders of sex development are due to congenital defects in chromosomal, gonadal, or anatomical sex development. The objective of this study was to determine the aetiology of this group of disorders in the Hong Kong Chinese population. Setting Five public hospitals in Hong Kong. Patients Patients with 46,XY disorders of sex development under the care of paediatric endocrinologists between July 2009 and June 2011. Main outcome measures Measurement of serum gonadotropins, adrenal and testicular hormones, and urinary steroid profiling. Mutational analysis of genes involved in sexual differentiation by direct DNA sequencing and multiplex ligation-dependent probe amplification. Results Overall, 64 patients were recruited for the study. Their age at presentation ranged from birth to 17 years. The majority presented with ambiguous external genitalia including micropenis and severe hypospadias. A few presented with delayed puberty and primary amenorrhea. Baseline and post-human chorionic gonadotropin-stimulated testosterone and dihydrotestosterone levels were not discriminatory in patients with or without AR gene mutations. Of the patients, 22 had a confirmed genetic disease, with 11 having 5α-reductase 2 deficiency, seven with androgen insensitivity syndrome, one each with cholesterol side-chain cleavage enzyme deficiency, Frasier syndrome, NR5A1-related sex reversal, and persistent Mullerian duct syndrome. Conclusions Our findings suggest that 5α-reductase 2 deficiency and androgen insensitivity syndrome are possibly the two most common causes of 46,XY disorders of sex development in the Hong Kong Chinese population. Since hormonal findings can be unreliable, mutational analysis of the SRD5A2 and AR genes should be considered the first-line tests for these patients.

Background Lipoprotein lipase (LPL) deficiency is a rare autosomal recessive disorder characterized by hypertriglyceridemia. The genetic defect lies in a mutation of the LPL gene. Methods A Chinese neonate with non-consanguineous parents was incidentally found to have hypertriglyceridemia. Mutation in her LPL gene was screened by using polymerase chain reaction and direct DNA sequencing. Results Homozygous missense mutations (L252V) were detected in the LPL gene of the patient. A novel nonsense mutation (C27X) was also identified. Conclusion Our finding supports L252V mutation in the LPL gene is a common mutation in Chinese with familial hyperchylomicronemia syndrome. DNA-based diagnosis in this syndrome is definitive. It saves the need for heparin-infusion test, which carries the risk of hemorrhage, and the measurement of LPL activity, which is tedious and is not widely available.

Recent reviews recommended the use of the aldosterone/renin ratio (ARR) to screen for primary hyperaldosteronism. However, widely different cutoff levels have been proposed, and test characteristics of ARR under different conditions of sampling are not known. We conducted a retrospective review among 45 subjects with carefully validated diagnoses of primary hyperaldosteronism and 17 subjects with essential hypertension to study the utility of ARR. Sixty-two patients with 75 sets of plasma renin activity (PRA), aldosterone, and ARR values from a postural study and 48 sets of values from a saline suppression test were analyzed. Ninety-four percent of these subjects underwent investigations because of hypokalemic hypertension.ARR yielded larger areas under the curve in the receiver-operating-characteristics curve than PRA or aldosterone under all conditions of testing. Our results confirmed the superiority of ARR to either aldosterone or PRA alone as a diagnostic test for primary hyperaldosteronism.ARR cutoff levels were significantly affected by the condition of testing. Depending on posture and time of day, it varied from 13.1-35.0 ng/dl per ng/ml.h in our study population. When using ARR for screening primary hyperaldosteronism, posture and time of sampling should be standardized both within and between centers to minimize variability in cutoff levels.

Acute intermittent porphyria (AIP) is an autosomal dominant, inborn error of the metabolism of heme biosynthesis caused by partial deficiency of hydroxymethylbilane synthase (HMBS). This enzyme catalyzes the condensation of four molecules of porphobilinogen to a tetrapyrrole, hydroxymethylbilane. AIP is characterized by acute attacks of a neurological disorder manifesting as abdominal pain, hypertension, tachycardia, peripheral neuropathy, and mental dysfunction. Biochemical diagnosis of AIP relies on increased urinary porphobilinogen and normal fecal porphyrin excretion (1). Identification of presymptomatic AIP carriers in families with affected individuals is of clinical importance because avoidance of precipitating agents (e.g., drugs and alcohol) can prevent the occurrence of the first porphyric attack, which may be life-threatening. However, there is a significant overlap between the enzyme activities of healthy individuals and patients with AIP (2). In addition, there is a variant of AIP, in which the red blood cell (RBC) HMBS activity is normal (3). DNA-based diagnosis of presymptomatic AIP has been more reliable than diagnosis by RBC HMBS activity, and, thus, direct detection of mutations in presymptomatic AIP is now the definitive approach. The human HMBS gene spans ∼10 kb of DNA on chromosome 11q24.1-24.2 and contains 15 exons (4). Extensive allelic heterogeneity has been demonstrated in this gene, and 159 mutations have been identified in the HMBS gene (5). Most of these mutations are found only in individual families, except those found in Dutch (R116W) (6) and Swedish (W198X) (7) AIP families. Although DNA sequencing can identify all the mutations, this approach is both labor-intensive and time-consuming (8). Several methods that accelerate mutational screening before sequencing have been developed, such as single-strand conformation polymorphism analysis (9), heteroduplex gel analysis (10), and denaturing gradient gel electrophoresis (11)(12). Recently, denaturing HPLC (DHPLC) appears to be more sensitive than other methods in mutation detection, as exemplified …

During the seven years from January 1989 to December 1995, we investigated 2,269 Chinese infants and young children for metabolic disorders in Hong Kong. These young patients, all aged under 4 years and originated from southern China, were ill with no apparent cause and had clinical manifestations suggestive of inherited metabolic diseases. A spot urine and a plasma sample were obtained from each patient for biochemical analysis, including urinary organic acid identification and plasma amino acid analysis. Six cases of mucopolysaccharidosis, four multiple carboxylase deficiency, three 2-methylacetoacetyl CoA thiolase deficiency, two methymalonic aciduria, one glutaric aciduria type I, one glutaric aciduria type II, one a-oxoglutaric aciduria, and one case of orotic aciduria were detected. There were also single suspected cases of medium-chain acyl-CoA dehydrogenase deficiency and isovaleric aciduria. No primary amino acid disorder, such as phenylketouria and maple syrup urine disease, has been detected. Our results suggest that a different pattern of inherited metabolic diseases exists in the southern Chinese when compared with the Chinese in other regions of China.

BACKGROUND 5α-Reductase 2 deficiency (5ARD) is a known cause of 46,XY disorders of sex development (DSD). Traditionally, the diagnosis relies on dihydrotestosterone (DHT) measurement, but the results are often equivocal, potentially leading to misdiagnosis. We reviewed alternative approaches for diagnosis of 5ARD. METHODS We conducted a retrospective review of the results of urinary steroid profiling (USP) by GC-MS and mutational analysis of SRD5A2 [steroid-5-alpha-reductase, alpha polypeptide 2 (3-oxo-5 alpha-steroid delta 4-dehydrogenase alpha 2)] by PCR and direct DNA sequencing of all 46,XY DSD patients referred to our laboratory with biochemical and/or genetic findings compatible with 5ARD. We also performed a literature review on the laboratory findings of all 5ARD cases reported in the past 10 years. RESULTS Of 16 patients diagnosed with 5ARD between January 2003 and July 2012, 15 underwent USP, and all showed characteristically low 5α- to 5β-reduced steroid metabolite ratios. Four patients had DHT measured, but 2 did not reach the diagnostic cutoff. In all 12 patients who underwent genetic analysis, 2 mutations of the SRD5A2 gene were detected to confirm the diagnosis. Twenty-four publications involving 149 patients with 5ARD were published in the review period. Fewer than half of these patients had DHT tested. Nearly 95% of them had the diagnosis confirmed genetically. CONCLUSIONS 5ARD can be confidently diagnosed by USP at 3 months postnatally and confirmed by mutational analysis of SRD5A2. Interpretation of DHT results may be problematic and is not essential in the diagnosis of 5ARD. We propose new diagnostic algorithms for 46,XY DSD.

Severe acute respiratory syndrome (SARS) is a contagious viral disease caused by a novel coronavirus (SARSCoV) and transmitted through droplets and close contact [1]. Healthcare workers (HCWs) are particularly at risk when looking after SARS patients. As reported by the World Health Organization [2] more than 20% (386) of those infected with SARS in Hong Kong were HCWs. Described here are the infection control procedures undertaken at a hospital in Hong Kong when three Caesarean sections were performed on women with active maternal SARS infection. SARS-CoV infection had been confirmed by reverse transcriptase polymerase chain reaction in all three mothers prior to the time of operation. The operations were performed between 1 April and 5 April 2003. None of the HCWs (>15) involved in the three separate operations developed fever or clinical SARS within 14 days of exposure. When the operations were performed, the Centers for Disease Control and Prevention (CDC; Atlanta, Ga., USA) had not yet prepared guidelines for the prevention of SARS transmission during Caesarean sections. Since these procedures are associated with the use of suction irrigation and diathermy, it was likely that body fluid and blood would spill and evaporate into the room during the operation. Therefore, the procedures were assumed to be aerosol generating, and previously described precautions to prevent contact and airborne infection were undertaken to prevent nosocomial SARS infection [3]. Although the CDC provided guidelines for the prevention and control of SARS infection on 6 May 2003 [4], those guidelines have, to the best of our knowledge, never been tested for the procedure described here. Following are the steps and procedures we undertook to prevent HCWs in our hospital from contracting SARS. For the three Caesarean sections performed on mothers with SARS, the number of healthcare workers was limited to a minimum, with only those personnel essential to carry out the operation, neonatal resuscitation, and cleanup being involved (i.e., 2 senior obstetricians, 2 senior neonatologists, 1 senior anaesthetist, 1 theatre assistant, a team of 4 senior midwives, and 2 cleansing staff). A nurse supervisor was designated as in-charge and was responsible for monitoring the other HCWs with regard to the use of personal protective equipment (PPE), cleansing of the room, sterilising the equipment and transferring the patients. She ensured all HCWs had fit-tested their respirators. She was also responsible for testing the portable high-efficiency particulate air filter (HEPA) units (Air-Mate PAPR; USA), checking the batteries, and training other HCWs on the proper use of the HEPA units. All unnecessary instruments were removed from the operating theatre. Extra laparotomy instruments were prepared to deal with possible intra-operative complications. Two bags of blood were made available in the theatre for the operation. Disposable instruments were used if available. To avoid spillage of blood, drapes with plastic bags on the sides were used. An operating theatre separate from the main theatre block was designated for this type of surgery in order to minimise contamination of the main theatre. The door of the operating theatre was kept closed during the operation, except when participating personnel entered or left the room. In order to keep the number of entrances and exits to a minimum during the operation, most of the equipment was prepared before the patient arrived. The air circulation was adjusted to 20 exchanges per minute. Negative pressure was created within the operating theatre relative to the adjacent room or hallway; thus, S. F. Wong ()) · K. M. Chow · Y. P. Leung · A. Chiu · P. W. Y. Lam · L. C. Ho Department of Obstetrics and Gynaecology, Maternal Fetal Medicine Unit, Princess Margaret Hospital, Lai Chi Kok, Kowloon, Hong Kong e-mail: shellwong@hotmail.com Tel.: +1-852-29901111 Fax: +1-852-29903488

An 8-year-old asymptomatic child was genetically diagnosed to have resistance to thyroid hormone (RTH) during a family screening. The disease-causing mutation is inherited from his father. Retrospective study showed the boy had a normal umbilical cord blood thyrotropin (TSH) level, suggesting that umbilical cord blood TSH may not reflect the fetal pituitary-thyroid axis abnormality and prenatal diagnosis and treatment should not be recommended in patients with mild RTH phenotype.

Capecitabine is an orally administered pro-drug of 5-fluorouracil that confers superior disease-free survival and presumably has a more favourable side-effect profile. Here we report on a patient who developed acute necrotising pancreatitis and very high triglyceride levels as well as hand-foot syndrome after receiving capecitabine for colonic cancer. Increased awareness of this potential side-effect and close monitoring of lipid levels may be warranted, especially in patients who have other conditions predisposing them to severe secondary hyperlipidaemia when using this drug.

We report on an adult patient with citrin deficiency in Hong Kong, in whom a novel mutation was identified. The patient presented with recurrent hyperammonaemic encephalopathy due to impairment of the liver urea cycle enzyme argininosuccinate synthetase. This autosomal recessive condition is also characterised by interesting food preferences, notably aversion to carbohydrates and craving for protein-rich and/or lipid-rich foods, as well as neuropsychiatric symptoms. Plasma amino acid analysis is very useful in revealing urea cycle disorders, and mutational analysis of the SLC25A13 gene can confirm the diagnosis.

Mucopolysaccharidosis VI (Maroteaux-Lamy syndrome) is a very rare inherited lysosomal storage disease. We evaluated the efficacy and safety of weekly infusions of recombinant human arylsulfatase B as enzyme replacement therapy for two patients in whom this condition was advanced. The primary outcome variables were the distance walked in a 6-minute walk test, forced vital capacity, and ejection fraction. The secondary outcome variables were the number of stairs climbed in a 3-minute stair climbing test, joint mobility, urinary glycosaminoglycan excretion, auto-continuous positive airway pressure study and liver size. After 24 weeks of treatment, patient A walked 40 m (36%) and patient B walked 66 m (58%) more in the walk test than at baseline. After 48 weeks, in patient A the corresponding improvements were 142 m (129%) in the walk test and 33 stairs (60%) in the 3-minute stair climbing test, and in patient B the respective improvements were 198 m (174%) and 77 stairs (140%). There was a significant decline in urinary glycosaminoglycan excretion and improvement in range of motion of joints in both patients. The auto-continuous positive airway pressure study revealed improvements in patient A, while other efficacy variables remained static. There were no drug-related adverse events or allergic reactions reported during and after the infusions of recombinant human arylsulfatase B. Recombinant human arylsulfatase B significantly improves endurance and reduces urinary glycosaminoglycan excretion. The drug is generally safe and well tolerated.

SUMMARY objective To study the age-related changes in bone density, serum parathyroid hormone, calcium absorption and other indices of calcium metabolism in Chinese women who habitually have a low calcium intake design Cross-sectional study subjects One hundred and fifty-six healthy Chinese women aged 20–83 years. None were on any medication or vitamin supplements. Subjects over the age of 60 years were all living in a hostel; younger subjects were nurses or subjects attending a family clinic for minor illnesses measurements Fasting blood and urine samples were collected for biochemical measurements and calcium absorption was measured using Ca by the method of Marshall and Nordin. Bone density was measured by dual energy X-ray densitometry (Norland X R20 X-ray bone densitometer) at the left hip and lumbar spine. Serum parathyroid hormone was measured by a chemiluminometric assay results Plasma Ionized calcium concentration, alkaline phosphatase, bicarbonate, plasma creatinine and serum B2 microgiobulin were significantly higher in the elderly than in the young, whereas plasma phosphate and the anion gap were higher in the young. Urinary excretion of calcium, phosphate and hydroxyproiine were all higher in older women. Plasma parathyroid hormone concentration was positively correlated with age even after taking into account the decline in renal function (as indicated by the rise in B2 microglobulin (r= 0·506, P > 0·001). Serum concentrations of 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D were not lower In the older women. Fractional calcium absorption from an oral load of radlolabelled calcium was slgnificantly lower in the older women and 37% of the older women were below the 2.5 percentile found in the younger women. Bone density measured by dual energy X-ray densitometry was also significantly lower in the elderly. conclusion In Chinese women there is an Increase in PTH and a decrease in calcium absorption with age in spite of the presence of normal vitamin D metabolites

It has been suggested that urinary steroid profiling may be used to provide information aiding the diagnosis and monitoring of adrenocortical carcinoma. Nonetheless, the abnormal patterns suggestive of adrenal malignancy are not well defined. We retrospectively studied the urinary steroid profiles of five patients with adrenocortical carcinoma at presentation and at follow-up, and compared these results with those from 76 patients with benign adrenocortical adenoma and 172 healthy controls. Three abnormal patterns of urinary steroid excretion were identified in patients with adrenocortical carcinoma at presentation and/or follow-up of residual disease: (1) hypersecretion in multiple steroid axes; (2) excretion of unusual metabolites, notably 5-pregnene-3alpha,16alpha,20alpha-triol, 5-pregnene-3beta,16alpha,20alpha-triol, and neonatal steroid metabolites in the post-neonatal period; (3) increase of tetrahydro-11-deoxycortisol relative to total cortisol metabolites. These preliminary findings offer ways in which urinary steroid profiling performed using gas chromatography-mass spectrometry can be helpful in the diagnosis and monitoring of adrenocortical carcinoma.

5Alpha-reductase 2 deficiency is an autosomal recessive disorder characterised by lack of masculinisation in XY individuals due to failure to convert testosterone to dihydrotestosterone, the bioactive androgen. Traditionally, the testosterone-to-dihydrotestosterone ratio is used to diagnose this condition but interpreting these results is not always straightforward, thus they may be inconclusive. On the contrary, urinary steroid profiling unambiguously demonstrates a significantly reduced excretion of 5alpha-reduced steroid metabolites compared to their 5beta counterparts. This analytical technique can also simultaneously confirm or rule out other causes of ambiguous genitalia due to steroidogenic defects. Making a DNA-based diagnosis by studying the SRD5A2 gene has become increasingly popular. Here, we report six Chinese patients from different families who were all diagnosed with 5alpha-reductase 2 deficiency based on urinary steroid profile findings and mutational analysis of the SRD5A2 gene. R227Q was the most commonly identified mutation in these patients. Management of sexual development disorders is also discussed.

Lipoprotein glomerulopathy is a rare kidney disease in which lipoprotein thrombi are seen in the glomerular capillaries. Most of these patients are found in Japan and East Asian countries. The presenting symptoms include proteinuria, an abnormal plasma lipoprotein profile that resembles type III hyperlipoproteinaemia, and a marked increase in serum apolipoprotein E concentration. Previous studies have suggested that lipoprotein glomerulopathy might be related to APOE gene mutation. No effective therapeutic regimen has been established for lipoprotein glomerulopathy. We report the first case of biopsy-proven lipoprotein glomerulopathy in Hong Kong in a patient who presented with nephrotic syndrome and dyslipidaemia. DNA analysis revealed apolipoprotein E Kyoto together with a novel apolipoprotein E mutation, apolipoprotein E (Asp230Tyr) Hong Kong. There was significant improvement in the clinical parameters and resolution of symptoms after the introduction of statins. Further studies will be needed to clarify the role of apolipoprotein E Hong Kong and its interaction with apolipoprotein E Kyoto in the pathogenesis of lipoprotein glomerulopathy.

Cryoglobulins are immunoglobulins that precipitate in the serum upon cooling to below core body temperature and re-dissolve at higher temperatures. Cryoglobulinaemia may be life-threatening. The three types of cryoglobulinaemia are associated with a wide spectrum of haematological, autoimmune, and chronic infectious diseases, especially hepatitis C infection. Our laboratory has received 378 requests for cryoglobulin testing over the past 5 years, with a detection rate of 4.8% in the 271 patients involved. Twelve per cent of the specimens were not processed due to being at an inappropriate temperature on arrival at the laboratory. Clinicians should be aware of temperature requirements when requesting cryoglobulin testing in suspected cases, and for all relevant protein tests in patients with cryoglobulinaemia. Handling specimens at inappropriate temperatures in the pre-analytical and analytical phases of the investigation might lead to cryoprecipitation and therefore false-negative results. The potential pitfalls encountered with specimen handling, analysis, and result interpretation are discussed in detail.

We report on three Chinese neonates with carnitine-acylcarnitine translocase deficiency. They presented within the first 48 hours of life. Two neonates were found in cardiac arrest; one of them survived after resuscitation. The third neonate suddenly developed cardiorespiratory insufficiency and succumbed eventually. The clustering of three cases in 5 years suggests that carnitine-acylcarnitine translocase deficiency is not rare in our Chinese population. We advocate that investigation for metabolic diseases including carnitine-acylcarnitine translocase deficiency should be performed in cases of sudden infant death and unexplained abrupt clinical deterioration in the early neonatal period. Non-ketotic hypoglycaemia is an early clue. The mainstay of initial treatment is glucose infusion at a rate greater than 7 mg/kg/minute, which inhibits beta-oxidation of fatty acids (the defective enzymatic steps in carnitine-acylcarnitine translocase deficiency) and thus prevents the accumulation of toxic long-chain acylcarnitines.

To evaluate the efficacy and safety of lithium in the treatment of thyrotoxicosis, and to study the dose and serum levels at which therapeutic response occurs.Retrospective study.Thyroid clinic of a regional hospital in Hong Kong.Thirteen patients with thyrotoxicosis pending therapy with radioiodine or surgery, in whom thionamides were contra-indicated due to adverse reactions or failure of treatment.Free thyroxine levels, time to euthyroidism, and side-effects of lithium.A satisfactory response, defined as a fall by 40% or more in free thyroxine levels and clinical improvement, was achieved in eight patients within 1 to 2 weeks of lithium therapy. In four others, response occurred in 3 to 5 weeks. Response was slow and inadequate in one patient due to 'escape'. The median dosage of lithium was 750 mg daily, with a range of 500 to 1500 mg daily. The median serum lithium level was 0.63 mmol/L. Lithium toxicity was observed in one patient.A relatively low dose of lithium offers a safe and effective alternative means of controlling thyrotoxicosis in patients who cannot tolerate or do not respond to thionamides.

To evaluate the relation between chorioamnionitis and hypotension in very low birthweight infants.Retrospective cohort study in infants with a birth weight of1500 g born between January 2002 and September 2004. The placentas were examined for evidence of chorioamnionitis and funisitis. Hypotension was defined by the use of vasopressors.Of 105 infants, 37 (35%) were chorioamnionitis positive. The onset of hypotension had a skewed distribution: day 1 for 30 episodes and scattered from day 2 to day 19 for the remaining 22. Of the 30 infants who developed hypotension on day 1, 17 (57%) were chorioamnionitis positive. The mean maturity of the chorioamnionitis positive group was 27.91 weeks, marginally less than the mean maturity of 29.05 weeks of the chorioamnionitis negative group (p = 0.05). After adjustment of the effects for confounding variables (birth weight, gestation, surfactant therapy, mechanical ventilation on day 1, high frequency oscillatory ventilation, patent ductus arteriosus), chorioamnionitis was the significant factor in line with hypotension developing on day 1 (adjusted odds ratio 5.14, 95% confidence interval 1.51 to 17.50). There was no evidence that hypotension developing after day 1 was associated with chorioamnionitis.There is a strong association between chorioamnionitis and hypotension developing on day 1 in very low birthweight infants.

We report on the first Chinese patient with triple-A syndrome, who presented at 22 months with status epilepticus secondary to hyponatraemia and hypoglycaemia. Subsequent endocrine investigations confirmed primary adrenal insufficiency and aldosterone deficiency. In the presence of achalasia and alacrima, this patient satisfies the diagnostic criteria of triple-A syndrome. Further molecular testing detected compound heterozygous mutations in the AAAS gene: a c.580C --> T transition in exon 7 and a c.771delG single nucleotide deletion in exon 8. Testing of parents and brother confirmed their heterozygous carrier status.

Congenital long QT syndrome is a rare hereditary disease that is related to the dysfunction of ion channels in cardiac cells. We report on a very rare case of its autosomal recessive form--the Jervell-Lange Nielsen syndrome--in a Pakistani family, which was diagnosed after the incidental finding of bradycardia in a newborn baby girl. We discuss the range of presentations in neonates; the importance of strong suspicion of the syndrome and family screening; the use of the diagnostic criteria and genetic tests; and the different management strategies.

A 74-year-old man was admitted for chest infection with acute exacerbation of chronic obstructive pulmonary disease. He was incidentally found to have an increased serum level of cardiac troponin I, despite the absence of symptoms and electrocardiographic evidence of ischaemic heart disease. Troponin I became undetectable after the serum was treated with polyethylene glycol, which removed any interfering antibodies. Serum cardiac troponin T was also undetectable after this treatment. Interference of the cardiac troponin I assay by heterophilic antibodies was thus confirmed. Because of the possibility of false-positive results due to immunoassay interference, clinicians should be alerted whenever laboratory findings are incompatible with the clinical picture, and should be ready to perform additional laboratory tests.

Background Butyrylcholinesterase (BCHE) deficiency is characterized by prolonged apnea after the use of certain muscle relaxants with the genetic defect lying in the BCHE gene. Methods Two Chinese patients with no serum BCHE activity were studied. The BCHE genes were screened for mutations by polymerase chain reaction and direct DNA sequencing. Results Of the four mutations detected, two novel mutations were identified in the two patients, i.e., F474L, and an insertion of an adenine between nucleotide positions 395 and 396. This information was used to screen the immediate families of the patients for carrier status. Conclusions We established the molecular basis of butyrylcholinesterase deficiency in two Chinese patients. The developed mutation detection assay provides a reliable method for identifying mutant BCHE carriers.

We report the results of biochemical and genetic studies in a Chinese family with familial dysalbuminaemic hyperthyroxinaemia. Total thyroxine levels were 1.2 to 1.7 times the upper limit of the reference range and free thyroxine levels were 1.2 to 1.6 times the upper reference limit. Concentrations of thyroid-stimulating hormone (thyrotropin) and free tri-iodothyronine were normal in all family members tested. Overall, thyroid function tests showed high total thyroxine levels in five males and two females over two generations in the family. The diagnosis of familial dysalbuminaemic hyperthyroxinaemia was confirmed by the detection of a guanine to adenine missense mutation in the second nucleotide of codon 218 of the gene encoding human serum albumin, showing that the mutation in this family is the same as that previously found in Caucasian populations.

Bone mineral density (BMD) has been shown to be increased in postmenopausal females with postthyroidectomy hypoparathyroidism, but it is not known whether similar gains occur in patients with idiopathic hypoparathyroidism. In this study, we measured the BMD of lumbar spine and proximal femur in 14 patients, 8 with idiopathic hypoparathyroidism and 6 with postthyroidectomy hypoparathyroidism, using dual-energy x-ray absorptiometry. Their age ranged from 23-57 yr old, with a mean of 42.5 yr. The results showed that patients with hypoparathyroidism had a higher BMD than the normal age- and sex-matched population. This was particularly evident at the lumbar spine (L2-L4), with positive Z-score of 1.93 +/- 1.03, whereas Z-score at the femoral neck was 1.14 +/- 0.62 SD. Subgroup analysis showed that those with postthyroidectomy hypoparathyroidism had a mean lumbar spine BMD of 1.434 g/cm(2) and femoral neck BMD of 1.026 g/cm(2), compared with a mean BMD of 1.364 g/cm(2) and 1.022 g/cm(2) at spine and hip, respectively, for those with idiopathic hypoparathyroidism. Statistical analysis did not reveal any significant difference in the BMD, T-score, and Z-score of the bone, at these two sites, between the two groups. In conclusion, the state of chronic hypoparathyroidism is associated with increased BMD, especially at the lumbar spine. Those with idiopathic hypoparathyroidism have a similar degree of increase in BMD as those with postthyroidectomy hypoparathyroidism.

Dihydropyrimidine dehydrogenase deficiency is an inborn error of pyrimidine metabolism characterised by thymine-uraciluria, convulsive disorders and developmental delay in paediatric patients, and an increased risk of toxicity from 5-fluorouracil treatment. This report is of the first patient with dihydropyrimidine dehydrogenase deficiency diagnosed in Hong Kong. The patient was a 2-day-old male neonate of Pakistani origin who presented with convulsions. Diagnosis was made by gas chromatographic-mass spectrometric detection of thymine-uraciluria and by molecular detection of a G to A point mutation in a 5'-splicing site leading to skipping of exon 14 in the DPYD gene of chromosome location 1q22. The results showed that the patient and his mother were homozygous and the father heterozygous for the splice site mutation. The mother also had thymine-uraciluria but was clinically asymptomatic.

To assess the clinical utility and safety of the low-dose corticotropin stimulation test in the diagnosis of secondary adrenocortical insufficiency.Prospective study.Regional hospital, Hong Kong.Seventy-two Chinese patients with suspected secondary adrenocortical insufficiency.Serum cortisol response during the low-dose corticotropin stimulation test, using the insulin tolerance test as the gold standard.The 30-minute cortisol level during the low-dose corticotropin stimulation test was most closely correlated (r=0.79) with the peak cortisol level achieved during the insulin tolerance test. The optimum sensitivity and specificity of the low-dose corticotropin stimulation test were obtained at a cut-off value of 550 nmol/L or more for the 30-minute cortisol level. Using the insulin tolerance test as the gold standard for comparison, the low-dose corticotropin stimulation test had a sensitivity of 97%, a specificity of 78%, a positive predictive value of 81%, and a negative predictive value of 97% at this cut-off value. The positive likelihood ratio was 4.4 and the negative likelihood ratio 0.04.The low-dose corticotropin stimulation test, using the cortisol response at 30 minutes after synacthen 1 microg is a safe, convenient, and sensitive method for screening abnormalities of the hypothalamic-pituitary-adrenocortical axis in Chinese patients suspected of having secondary adrenocortical insufficiency.

Urea and creatinine levels in spent hemodialysates showed only small declines in spite of incubation at 37 degrees C for 36 hours. In the determination of dialysate-side solute removal, it would seem prudent to keep spent dialysate cold during collection to retard bacterial breakdown of these waste products.

Malignant phaeochromocytoma is defined as the presence of tumour deposits at sites that are normally devoid of chromaffin cells. We report on a 63-year-old man who had a giant malignant phaeochromocytoma of the right adrenal gland that encased the inferior vena cava. The urinary excretion rates of catecholamines and their metabolites were normal, except for normetanephrine, which was excreted at a higher rate than normal. The tumour was surgically unresectable by laparotomy. Postoperatively, the patient was given a 4-month trial of subcutaneous octreotide and intravenous meta-iodobenzylguanidine I 131. Occult lung secondary tumours were first detected by meta-iodobenzylguanidine scintigraphy after 2 years, and the patient died of bone and lung metastases 1 year later. Because phaeochromocytoma is rare, local experience in managing this disease is limited. This report alerts physicians of the methods of diagnosing and managing surgically unresectable malignant phaeochromocytoma.

Many studies showed an increased occurrence of primary hyperparathyroidism during lithium therapy. We studied 53 patients receiving lithium therapy prospectively for 2 yr. Serum PTH levels were unequivocally elevated. The baseline PTH level was 2.8 +/- 1.2 pmol/L and increased progressively to 3.9 +/- 1.5 pmol/L after 2 yr (P0.0005). There was no change in serum calcium, alkaline phosphatase, inorganic phosphate concentrations or tubular reabsorption of phosphate in relation to glomerular filtration rate. Fasting urinary reabsorption of calcium increased significantly (P0.0005), which was concordant with the PTH change. Fasting and 24-h urinary excretion of calcium decreased significantly (P0.0005), suggesting reduced, rather than enhanced, bone resorption as in primary hyperparathyroidism. This may be the main mechanism in maintaining normocalcemia, despite PTH elevation, during lithium therapy.

Glycogen storage disease type la (GSD1a) is an autosomal recessive metabolic disorder caused by a deficiency in glucose-6-phosphatase (G6Pase). We analyzed the G6Pase genes of two unrelated Chinese families with GSD1a. DNA sequencing of all five exons and the exon-intron boundaries revealed a G T transversion at nucleotide 727 (727G--T) in exon 5, which has previously been reported to cause abnormal splicing. In one family, the subject and her affected sister were confirmed to be homozygous for this mutation and their parents to be heterozygotes. In the other family, the proband was identified to be heterozygous for this mutation, and a novel mutation, the 341delG in exon 2, was identified. This mutation alters the reading frame and creates a stop codon TAA 15 codons downstream from the mutation, resulting in a truncated protein. Family studies revealed that the father was heterozygous for the 727G--T mutation and that the mother was heterozygous for the 341delG mutation. This is the first time that the 727G T mutation has been found in Chinese patients or outside Japan. Since we only tested two GSD1a families and found 727G--T in both, we believe that this mutation may also be prevalent in our local Chinese population. To investigate allele frequencies, we screened 385 Chinese healthy volunteers and found two asymptomatic carriers. Our findings suggest that the 727G--T mutation is indeed prevalent in Hong Kong.

During the seven years from January 1989 to December 1995, we investigated 2,269 Chinese infants and young children for metabolic disorders in Hong Kong. These young patients, all aged under 4 years and originated from southern China, were ill with no apparent cause and had clinical manifestations suggestive of inherited metabolic diseases. A spot urine and a plasma sample were obtained from each patient for biochemical analysis, including urinary organic acid identification and plasma amino acid analysis. Six cases of mucopolysaccharidosis, four multiple carboxylase deficiency, three 2-methylacetoacetyl CoA thiolase deficiency, two methymalonic aciduria, one glutaric aciduria type I, one glutaric aciduria type II, one a-oxoglutaric aciduria, and one case of orotic aciduria were detected. There were also single suspected cases of medium-chain acyl-CoA dehydrogenase deficiency and isovaleric aciduria. No primary amino acid disorder, such as phenylketouria and maple syrup urine disease, has been detected. Our results suggest that a different pattern of inherited metabolic diseases exists in the southern Chinese when compared with the Chinese in other regions of China.

This study validates Ing's partial dialysate collection method, which employs proportionate collection using a side tube capped with a small-gauge plastic needle. The urea nitrogen and creatinine levels of the small representative fraction of spent dialysate collected in the above fashion are undistinguishable from those obtained from the total spent dialysate. The estimated urea nitrogen removed during hemodialysis using this approach is similar to that using the total dialysate collection method; Ing's method is simple and useful in quantifying the dialysis dosage and in its assessment of the nutritional status of patients on hemodialysis.

Summary We report a case of congenital adrenal hyperplasia due to 17 α-hydroxylase deficiency in a Chinese genotypic male patient. Despite the male genotype, normal female external genitalia were present and with the introduction of cyclical oestrogen therapy withdrawal bleeding occurred, confirming the presence of functional endometrial tissue. We believe this to be the first report of persistent Mullerian duct structures in a genotypic male with 17 alpha-hydroxylase deficiency. It could be explained by either impaired secretion or impaired action of anti-Mullerian hormone. Further, contrary to the usual finding of suppressed aldosterone secretion, this patient had measurable levels of plasma aldosterone.

The prevalence of hypercalcemia in tuberculosis in Hong Kong and its occurrence in relation to the radiographic extent of disease were studied in 57 patients with sputum smear (n = 44) and/or culture positive (n = 13) pulmonary tuberculosis and in five patients with military tuberculosis prior to treatment. Only one (1.6%) patient had a corrected plasma calcium level above the reference range for our laboratory. There was a positive relationship between the corrected plasma calcium levels and the radiographic extent of disease (r = 0.37), p0.01). As the occurrence of hypercalcemia in tuberculosis is known to be influenced by the calcium intake, our finding of a low prevalence of "absolute" hypercalcemia in Hong Kong could be related to the low dietary calcium intake in these subjects.

SUMMARY objective To study the relationship between the excretion of nephrogenous cyclic AMP (NcAMP) and other blood and urine parameters as an index of PTH-like activity in patients with primary hepatocellular carcinoma design After overnight fast, a double voided urine and a blood sample were collected from each subject for determination of various anaytes and results compared between various groups patients Fifty-five consecutive untreated patients with primary hepatocellular carcinoma, 14 healthy controls and eight patients with cirrhosis only measurements Serum calcium, phosphate, aikaline phosphatase, albumin, creatinine and urinary calcium, creatnine and hydroxyproline were measured by routine methods. cAMP was measured in plasma and urine by a radioimmunoassay (Dioagnostic Products Corporation) and PTH measured in serum by an immunoradiometric assay (Nichols Institute). TmP/GFR, NcAMP etc. were calculated according to various published methods results Four out of 55 patients (7%) with primary hepatocellular carcinoma had hypercalcaemia. These four patients had significantly lower (P > 0·05) phosphate, PTH and TmP/GFR and elevated NcAMP (P > 0·001) compared with normocalcaemic hepatocellular carcinoma and cirrhotic patients, and healthy controls. The excretion of hydroxyproline and calcium was significantly elevated (P > 0·001) in the hypercalcaemic patients. Bone resorption was found to be the major cause of hypercaicaemia in three of the four hypercalcaemic patients. Fifteen hepatocellular carcinoma patients (29%) with normocalcaemia had suppressed PTH. conclusion We conciude that a PTH-like humoral factor such as PTH related peptide is the cause of hypercalcaemia in patients with primary hepatocellular carcinoma, and that in some normocalcaemic patients with this tumour PTH is suppressed

The frequency, causes, and outcome of hyponatremia (plasma sodium less than 125 mmol/L), and the value of some routine investigations were studied during a six month period in a hospital population. The incidence and prevalence of hyponatremia were 1.5 and 2.6 per 100 patients per day, respectively. A majority of patients (75%) developed hyponatremia in the hospital. The commonest cause of hyponatremia was normovolemic hyponatremia (79 patients). Hypovolemic and hypervolemic hyponatremia were seen in 63 and 21 patients, respectively. Urine osmolality did not differ between the three groups, and was of little diagnostic value. The mortality in the hyponatremic patients was 41.7%.

Serum iron, total iron binding capacity (TIBC) and serum ferritin were measured on 419 samples to evaluate the value of these measurements and to develop a cost effective strategy for diagnosis of iron deficiency. If transferrin saturation (PS) of less than 16% and TIBC of greater than 70 mumol/L were used as diagnostic criteria for iron deficiency, 93% of the 59 patients who fulfilled these criteria were iron deficient; 49 had low serum ferritin and six were iron deficient with normal serum ferritin levels. When we used PS of greater than or equal to 22% and TIBC less than or equal to 70 mumol/L to exclude iron deficiency, 99% of those patients who fulfilled these criteria had normal serum ferritin levels. We, therefore, suggest that for biochemical diagnosis of iron deficiency serum iron and TIBC should be done first, and serum ferritin is not required when the PS is less than 16% and TIBC greater than 70 mumol/l or if PS is greater than or equal to 22% and TIBC less than or equal to 70 mumol/L. In all other cases serum ferritin is measured to detect iron deficiency. This approach will save 35 to 40% of reagent costs.