Publications by authors named "Nike Kwai Cheung Lau"

12 Publications

  • Page 1 of 1

Nuclear magnetic resonance spectroscopy-based urinalysis for a young girl with extreme hypoglycaemia.

Pathology 2021 Oct 23. Epub 2021 Oct 23.

Division of Chemical Pathology, Department of Pathology, Queen Mary Hospital, Hong Kong, China; Department of Pathology, The University of Hong Kong, Hong Kong, China. Electronic address:

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http://dx.doi.org/10.1016/j.pathol.2021.07.013DOI Listing
October 2021

Urine organic acid as the first clue towards aromatic L-amino acid decarboxylase (AADC) deficiency in a high prevalence area.

Clin Chim Acta 2021 Oct 20;521:40-44. Epub 2021 Jun 20.

Department of Pathology, Queen Mary Hospital, Hong Kong, China; Department of Pathology, The University of Hong Kong, Hong Kong, China. Electronic address:

Background: Aromatic L-amino acid decarboxylase deficiency is a rare neurometabolic disease due to impaired decarboxylation of neurotransmitter precursors to its active form.

Case: We retrospectively reviewed 8 cases from 2008 to 2019 with cerebrospinal fluid neurotransmitter analysis performed at our centre. All cases had an elevated urine vanillactic acid and, in most cases, with N-acetylvanilalanine detected. Cerebrospinal fluid analysis showed low downstream metabolites vanillylmandelic acid, homovanillic acid but high 3-O-methyl-L-DOPA, 5-hydroxytryptophan. Cerebrospinal fluid pterins were normal. Genotyping in DDC confirms the diagnosis. Urine organic acid analysis provided the first clue to diagnosis in four of the cases, which then triggered cerebrospinal fluid neurotransmitter and genetic analysis. We also developed a diagnostic decision support system to assist the interpretation of the mass spectrometry data from urine organic acids.

Conclusions: Urine organic acid could be essential in guiding subsequent investigations for the diagnosis of aromatic L-amino acid decarboxylase deficiency. We propose to screen suspected cases first with urine organic acids, specifically looking for vanillactic acid and N-acetylvanilalanine. Suggestive findings should be followed with target analysis for c.714 + 4A > T in ethnically Chinese patients. The assistive tool allowed expedite interpretation of profile data generated from urine organic acids analysis. It may also reduce interpreter's bias when peaks of interest are minor peaks in the spectrum.
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http://dx.doi.org/10.1016/j.cca.2021.06.025DOI Listing
October 2021

Serum ceruloplasmin monitoring in a case of silver intoxication due to intravenous silver infusion.

Clin Toxicol (Phila) 2021 May 28:1-4. Epub 2021 May 28.

Division of Chemical Pathology, Department of Pathology, Queen Mary Hospital, Hong Kong, China.

Introduction: Colloidal silver packaged as a dietary supplement is readily available online and is thought to be safe. Literature describing its toxicity in humans is scarce.

Case Report: A 47-year-old man presented to us for sensory and gait problems. He had unremarkable past health except dystrophic nails. He further volunteered a history of receiving chronic oral and intravenous administration of colloidal silver. We confirmed his plasma silver was 1200-fold elevated, measuring 11990 nmol/L (normal < 10 nmol/L). He had deranged liver function tests, and liver biopsy showed distorted acinar architecture, bridging fibrosis and lymphocytic infiltrate with silver particles clustering along the vascular endothelium and portal venules. Brain magnetic resonance imagining showed features of mineralization over bilateral globus pallidi. There was biochemical evidence of central adrenal insufficiency, intracellular iron overload and hypoceruloplasminemia (<0.05 g/L). Gradual clinical and biochemical improvement was noted after silver cessation: his plasma silver dropped to 4800 nmol/L (3 months) and 1650 nmol/L (12 months), and serum ceruloplasmin reverted to 0.13 g/L (10 months) and 0.29 g/L (20 months).

Conclusions: The potential effects of silver to liver and copper metabolism were shown in this case. Serum ceruloplasmin also serves as a surrogate marker in monitoring silver intoxication.
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http://dx.doi.org/10.1080/15563650.2021.1919692DOI Listing
May 2021

In-house multiplex ligation-dependent probe amplification assay for citrin deficiency: analytical validation and novel exonic deletions in SLC25A13.

Pathology 2021 Dec 25;53(7):867-874. Epub 2021 May 25.

Kowloon West Cluster Laboratory Genetic Service, Chemical Pathology Laboratory, Department of Pathology, Princess Margaret Hospital, Hong Kong, China. Electronic address:

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.
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http://dx.doi.org/10.1016/j.pathol.2021.02.010DOI Listing
December 2021

McArdle disease presenting as abnormal liver function: biochemical, anatomical and genetic characterisation in the first genetically confirmed Chinese family with a novel splicing variant.

Pathology 2021 08 10;53(5):670-673. Epub 2020 Dec 10.

Kowloon West Cluster Laboratory Genetic Service, Chemical Pathology Laboratory, Department of Pathology, Princess Margaret Hospital, Hong Kong. Electronic address:

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http://dx.doi.org/10.1016/j.pathol.2020.09.019DOI Listing
August 2021

Toxicity from illegitimate slimming agents - a 10-year case series at a tertiary toxicology laboratory in Hong Kong.

Clin Toxicol (Phila) 2021 May 22;59(5):426-432. Epub 2020 Sep 22.

Hospital Authority Toxicology Reference Laboratory, Princess Margaret Hospital, Kowloon, Hong Kong.

Context: This retrospective case-series study aims to provide an overview of the clinical, biochemical and analytical findings in patients who presented with toxicity related to the use of illegitimate slimming agents in Hong Kong from the perspective of a tertiary referral toxicology laboratory.

Methods: All clinical cases referred to the Hospital Authority Toxicology Reference Laboratory, Hong Kong with clinical suspicion of illegitimate slimming agent-related toxicity between January 2008 and December 2017 were reviewed retrospectively. The use of illegitimate slimming agents included the use of (1) deregistered slimming agents, (2) drug analogues that were not registered drugs, (3) registered drugs not approved for the indication of weight reduction (whether prescribed by a doctor or not), and (4) prescription-only slimming agents without a doctor's prescription. Patients taking registered weight-reducing drugs prescribed by a doctor were excluded. Patient demographics, clinical features, relevant laboratory investigations, and toxicological findings were analyzed.

Results: From 2008 to 2017, a total of 346 patients were analytically confirmed by our laboratory to have clinical toxicity related to the use of illegitimate slimming agents. The median age of the patients was 27 years and 92.5% of the patients were female. The most common clinical presentations included psychiatric features, sympathomimetic toxicity, hypokalemia, and abnormal thyroid function tests. Fatal or severe clinical toxicity was observed in 10% of the cases. The major classes of drugs detected on our analytical platforms were stimulants (e.g., sibutramine), laxatives (e.g., anthraquinones), diuretics (e.g., hydrochlorothiazide), and thyroid hormones (e.g., animal thyroid tissue). These illegitimate slimming agents were obtained from various sources including the Internet, over-the-counter in community pharmacy, or unspecified local sources.

Discussion And Conclusions: The use of slimming agents is common worldwide; apart from taking registered slimming agents prescribed by registered practitioners, many users obtain slimming agents from various illegitimate sources. The unregulated use of these drugs can be associated with significant clinical toxicity. This study provides a current landscape of illegitimate slimming agent toxicity in Hong Kong to frontline clinicians and other toxicology professionals. Collaboration between clinicians, laboratories, and government authorities would be imperative to prevent further health adversities related to the misuse of these agents.
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http://dx.doi.org/10.1080/15563650.2020.1822529DOI Listing
May 2021

Tiletamine detected in a ketamine abuser with altered mental status.

Clin Toxicol (Phila) 2020 05 13;58(5):430-431. Epub 2019 Aug 13.

Emergency Medicine Unit, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, China.

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http://dx.doi.org/10.1080/15563650.2019.1650938DOI Listing
May 2020

Urinary bladder stone due to adenine phosphoribosyltransferase deficiency: first genetically confirmed case in a Chinese patient.

Pathology 2019 Aug 12;51(5):557-561. Epub 2019 Jun 12.

Department of Chemical Pathology, Prince of Wales Hospital, Hong Kong. Electronic address:

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http://dx.doi.org/10.1016/j.pathol.2019.02.008DOI Listing
August 2019

First case of genetically confirmed CLN3 disease in Chinese with cDNA sequencing revealing pathogenicity of a novel splice site variant.

Clin Chim Acta 2018 Nov 24;486:151-155. Epub 2018 Jul 24.

Kowloon West Cluster Laboratory Genetic Service, Chemical Pathology Laboratory, Department of Pathology, Princess Margaret Hospital, Hong Kong. Electronic address:

Background: Juvenile neuronal ceroid lipofuscinosis (CLN3 disease) is a hereditary progressive neurodegenerative disease well documented among Caucasians, but such clinical data and genetic characterization is lacking among Asian populations.

Patient And Methods: A 13-year-old Chinese girl presented for diagnostic evaluation with retinitis pigmentosa, generalised tonic-clonic seizure and cerebellar ataxia. Electron microscopy of whole blood and skin biopsy, and mutation analysis of CLN3 gene with genomic DNA and cDNA, were performed.

Results: Electron microscopy showed vacuolated lymphocytes, and characteristic patterns in eccrine glands suggestive of neuronal ceroid lipofuscinosis. Sequencing of genomic DNA showed homozygous splice site variant NM_000086.2(CLN3):c.906+6T>G, and the pathogenicity of which was confirmed by cDNA sequencing to demonstrate the deletion of a transmembrane domain of the CLN3 protein. The mutant protein was predicted to adversely affect ligand binding of CLN3 as a lysosomal membrane protein.

Conclusions: Here we report the first genetically confirmed CLN3 disease in Chinese, with a novel splice site variant with proposed pathogenetic mechanism relating gene and protein, and highlights the potential ethnic differences in the mutation spectrum. We wish to establish the importance of clinical awareness and laboratory diagnosis of CLN3 disease, especially in the promising age of gene therapy.
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http://dx.doi.org/10.1016/j.cca.2018.07.040DOI Listing
November 2018

Genetic diagnosis of CADASIL in three Hong Kong Chinese patients: A novel mutation within the intracellular domain of NOTCH3.

J Clin Neurosci 2018 Oct 3;56:95-100. Epub 2018 Jul 3.

Kowloon West Cluster Laboratory Genetic Service, Chemical Pathology Laboratory, Department of Pathology, Princess Margaret Hospital, Hong Kong Special Administrative Region. Electronic address:

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an adult onset hereditary stroke syndrome characterized by recurrent stroke and progressive cognitive impairment caused by NOTCH3 mutations. We report here the clinical and molecular findings of three unrelated Hong Kong Chinese families with CADASIL syndrome. Sanger sequencing of genomic DNA revealed a novel heterozygous variant NM_000435.2(NOTCH3):c.[5903_5904insATAA];[5903_5904=] NP_000426.2:p.(Asp1969);(Asp1969=) and two previously reported heterozygous mutations NM_000435.2(NOTCH3):c.[328C>T];[328C=] NP_000426.2:p.[(Arg110Cys)];[(Arg110=)] and NM_000435.2(NOTCH3):c.[580T>A];[580T=] NP_000426.2:p.(Cys194Ser);(Cys194=) in the three families respectively. Molecular basis of CADASIL in these three patients were further established. Genetic analysis provides a reliable method for confirming the diagnosis of CADASIL and enables proper genetic counseling and cascade testing.
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http://dx.doi.org/10.1016/j.jocn.2018.06.050DOI Listing
October 2018

Adulteration of proprietary Chinese medicines and health products with undeclared drugs: experience of a tertiary toxicology laboratory in Hong Kong.

Br J Clin Pharmacol 2018 Jan 4;84(1):172-178. Epub 2017 Oct 4.

Hospital Authority Toxicology Reference Laboratory, Princess Margaret Hospital, Hong Kong.

Aims: Proprietary Chinese medicines (pCMs) and health products, generally believed to be natural and safe, are gaining popularity worldwide. However, the safety of pCMs and health products has been severely compromised by the practice of adulteration. The current study aimed to examine the problem of adulteration of pCMs and health products in Hong Kong.

Methods: The present study was conducted in a tertiary referral clinical toxicology laboratory in Hong Kong. All cases involving the use of pCMs or health products, which were subsequently confirmed to contain undeclared adulterants, from 2005 to 2015 were reviewed retrospectively.

Results: A total of 404 cases involving the use of 487 adulterated pCMs or health products with a total of 1234 adulterants were identified. The adulterants consisted of approved drugs, banned drugs, drug analogues and animal thyroid tissue. The six most common categories of adulterants detected were nonsteroidal anti-inflammatory drugs (17.7%), anorectics (15.3%), corticosteroids (13.8%), diuretics and laxatives (11.4%), oral antidiabetic agents (10.0%) and erectile dysfunction drugs (6.0%). Sibutramine was the most common adulterant (n = 155). The reported sources of these illicit products included over-the-counter drug stores, the internet and Chinese medicine practitioners. A significant proportion of patients (65.1%) had adverse effects attributable to these illicit products, including 14 severe and two fatal cases. Psychosis, iatrogenic Cushing syndrome and hypoglycaemia were the three most frequently encountered adverse effects.

Conclusions: Adulteration of pCMs and health products with undeclared drugs poses severe health hazards. Public education and effective regulatory measures are essential to address the problem.
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http://dx.doi.org/10.1111/bcp.13420DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5736835PMC
January 2018
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