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Papers by CHI KIN Lai
Clinica Chimica Acta, 2015
Beta-ketothiolase deficiency is a rare inborn errors of metabolism (IEM) affecting the catabolism... more Beta-ketothiolase deficiency is a rare inborn errors of metabolism (IEM) affecting the catabolism of isoleucine, characterized by severe ketoacidosis in children of 6 to 24months old. A prompt diagnosis is of paramount importance as the metabolic decompensation can be effectively reverted by glucose infusion and health outcomes are improved on a protein-restricted diet. Currently, majority of the laboratory diagnosis were made based on mass-spectrometry and molecular genetics while little is mentioned on the advancement of nuclear magnetic resonance (NMR) spectroscopy for the diagnosis of this condition. We report a case of beta-ketothiolase deficiency in a 1-y-old Chinese boy who presented with repeated vomiting, impaired consciousness and severe ketoacidosis. NMR urinalysis detected excessive amount of butanone (a disease specific marker of beta-ketothiolase deficiency), tiglylglycine, (intermediate of isoleucine catabolism) and ketones. Diagnosis of beta-ketothiolase deficiency was further established by molecular genetic studies of ACAT1 gene of the proband. This case illustrated that NMR-based urinalysis is complementary to organic acid analysis for diagnosis of beta-ketothiolase deficiency. The operation of NMR is simple and fast; sample preparation is a two-step procedure while the NMR acquisition is automatic and usually takes <15min. We envisage that NMR analysis will become more available in clinical laboratories and will play an important role in acute pediatric care.
Clinica Chimica Acta, 2012
Background: The diagnosis of aromatic L-amino acid decarboxylase (AADC) deficiency, one of the pe... more Background: The diagnosis of aromatic L-amino acid decarboxylase (AADC) deficiency, one of the pediatric neurotransmitter disorders, is classically made with plasma enzyme level or cerebrospinal fluid (CSF) neurotransmitter profile, while both are technically demanding and the latter requires the invasive lumbar puncture. So far less than 100 cases have been reported worldwide with 20% from Taiwan. It was postulated that the condition might have been under-diagnosed among Chinese populations and a non-invasive screening tool should be developed in areas with high prevalence. Methods: Urine metabolic profiles performed by gas chromatography-mass spectrometry (GC-MS) in a 31-month period were retrospectively reviewed: those with vanilmandelic acid concentration lower than one percentile plus the presence of 3-o-methyldopa were defined as positive and the patients were further evaluated. Results: Among 1046 metabolic profiles (from 845 patients) reviewed, 3 profiles from 2 patients were screened positive: both cases had compatible CSF neurotransmitter profiles and the diagnosis was further confirmed by genetic analysis of DDC gene. 13 negative urinary metabolic profiles from 7 patients who had CSF neurotransmitters analyzed were identified as controls: all 7 CSF neurotransmitter profiles were not compatible for AADC deficiency. Conclusions: The GC-MS-based urine metabolic profiling was shown to be a satisfactory screening tool for AADC deficiency. Further confirmation can be performed by mutation analysis in the DDC gene, thus avoiding risks of lumbar puncture. We advocate all ethnic Chinese patients presenting with dystonia have their urine organic acids analyzed before proceeding to CSF neurotransmitters analysis.
American Journal of Kidney Diseases, 2005
The authors report a case of unexplained nephropathy 2 months after ingestion of Herba Aristoloch... more The authors report a case of unexplained nephropathy 2 months after ingestion of Herba Aristolochia Mollissemae in a patient with long-standing Crohn's disease and recently diagnosed carcinoma of the colon. It presented as a relentlessly progressing hypocellular interstitial nephritis 5 months after cessation of an earlier course of mesalazine. The patient finally had end-stage renal failure 12 months after taking herbs and required hemodialysis. Aristolochic acid (AA) was detected in the herbal sample of Herba Aristolochia Mollissemae by high-performance liquid chromatography-diode array detection and electrospray ionization-tandem mass spectrometry. Specific AA-DNA adducts were detected in the renal biopsy by 32 P-postlabelling analysis. Transitional cell carcinoma was diagnosed 5 months after herb ingestion. It was found that the originally prescribed nonnephrotoxic herb had been substituted by AA-containing Herba Aristolochia Mollissemae at the wholesaler level. Although AA-associated nephropathy could not be proved conclusively, the current case contributed to the withdrawal of the AA-related herbs by the local health authority in Hong Kong. Physicians should be on the alert for herbal nephrotoxicity by possible replacement of nontoxic herbs by nephrotoxic herbs. Am J Kidney Dis 45:407-410.
Clinica Chimica Acta, 2015
Beta-ketothiolase deficiency is a rare inborn errors of metabolism (IEM) affecting the catabolism... more Beta-ketothiolase deficiency is a rare inborn errors of metabolism (IEM) affecting the catabolism of isoleucine, characterized by severe ketoacidosis in children of 6 to 24months old. A prompt diagnosis is of paramount importance as the metabolic decompensation can be effectively reverted by glucose infusion and health outcomes are improved on a protein-restricted diet. Currently, majority of the laboratory diagnosis were made based on mass-spectrometry and molecular genetics while little is mentioned on the advancement of nuclear magnetic resonance (NMR) spectroscopy for the diagnosis of this condition. We report a case of beta-ketothiolase deficiency in a 1-y-old Chinese boy who presented with repeated vomiting, impaired consciousness and severe ketoacidosis. NMR urinalysis detected excessive amount of butanone (a disease specific marker of beta-ketothiolase deficiency), tiglylglycine, (intermediate of isoleucine catabolism) and ketones. Diagnosis of beta-ketothiolase deficiency was further established by molecular genetic studies of ACAT1 gene of the proband. This case illustrated that NMR-based urinalysis is complementary to organic acid analysis for diagnosis of beta-ketothiolase deficiency. The operation of NMR is simple and fast; sample preparation is a two-step procedure while the NMR acquisition is automatic and usually takes <15min. We envisage that NMR analysis will become more available in clinical laboratories and will play an important role in acute pediatric care.
Clinica Chimica Acta, 2012
Background: The diagnosis of aromatic L-amino acid decarboxylase (AADC) deficiency, one of the pe... more Background: The diagnosis of aromatic L-amino acid decarboxylase (AADC) deficiency, one of the pediatric neurotransmitter disorders, is classically made with plasma enzyme level or cerebrospinal fluid (CSF) neurotransmitter profile, while both are technically demanding and the latter requires the invasive lumbar puncture. So far less than 100 cases have been reported worldwide with 20% from Taiwan. It was postulated that the condition might have been under-diagnosed among Chinese populations and a non-invasive screening tool should be developed in areas with high prevalence. Methods: Urine metabolic profiles performed by gas chromatography-mass spectrometry (GC-MS) in a 31-month period were retrospectively reviewed: those with vanilmandelic acid concentration lower than one percentile plus the presence of 3-o-methyldopa were defined as positive and the patients were further evaluated. Results: Among 1046 metabolic profiles (from 845 patients) reviewed, 3 profiles from 2 patients were screened positive: both cases had compatible CSF neurotransmitter profiles and the diagnosis was further confirmed by genetic analysis of DDC gene. 13 negative urinary metabolic profiles from 7 patients who had CSF neurotransmitters analyzed were identified as controls: all 7 CSF neurotransmitter profiles were not compatible for AADC deficiency. Conclusions: The GC-MS-based urine metabolic profiling was shown to be a satisfactory screening tool for AADC deficiency. Further confirmation can be performed by mutation analysis in the DDC gene, thus avoiding risks of lumbar puncture. We advocate all ethnic Chinese patients presenting with dystonia have their urine organic acids analyzed before proceeding to CSF neurotransmitters analysis.
American Journal of Kidney Diseases, 2005
The authors report a case of unexplained nephropathy 2 months after ingestion of Herba Aristoloch... more The authors report a case of unexplained nephropathy 2 months after ingestion of Herba Aristolochia Mollissemae in a patient with long-standing Crohn's disease and recently diagnosed carcinoma of the colon. It presented as a relentlessly progressing hypocellular interstitial nephritis 5 months after cessation of an earlier course of mesalazine. The patient finally had end-stage renal failure 12 months after taking herbs and required hemodialysis. Aristolochic acid (AA) was detected in the herbal sample of Herba Aristolochia Mollissemae by high-performance liquid chromatography-diode array detection and electrospray ionization-tandem mass spectrometry. Specific AA-DNA adducts were detected in the renal biopsy by 32 P-postlabelling analysis. Transitional cell carcinoma was diagnosed 5 months after herb ingestion. It was found that the originally prescribed nonnephrotoxic herb had been substituted by AA-containing Herba Aristolochia Mollissemae at the wholesaler level. Although AA-associated nephropathy could not be proved conclusively, the current case contributed to the withdrawal of the AA-related herbs by the local health authority in Hong Kong. Physicians should be on the alert for herbal nephrotoxicity by possible replacement of nontoxic herbs by nephrotoxic herbs. Am J Kidney Dis 45:407-410.