Publications by authors named "Toby Chun-Hei Chan"

DNAJC12 deficiency is a recently described inherited metabolic disorder resulting in hyperphenylalaninemia and neurotransmitter deficiency. The effect of treatment on the prevention of neurological manifestations in this newly reported and heterogenous disorder is not fully understood, and the optimal treatment strategy remains to be elucidated. The global or regional incidence of the disease is yet to be estimated.

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Background: Patient registries are crucial for rare disease management. However, manual registry construction is labor-intensive and often not user-friendly. Our goal is to establish Hong Kong's first computer-assisted patient identification tool for rare diseases, starting with inborn errors of metabolism (IEM).

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Newborn screening (NBS) is an important public health program that aims to identify pre-symptomatic healthy babies that will develop significant disease if left undiagnosed and untreated. The number of conditions being screened globally is expanding rapidly in parallel with advances in technology, diagnosis, and treatment availability for these conditions. In Hong Kong, NBS for inborn errors of metabolism (NBSIEM) began as a pilot program in October 2015 and was implemented to all birthing hospitals within the public healthcare system in phases, with completion in October 2020.

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In this study, we evaluated the implementation of a second-tier genetic screening test using an amplicon-based next-generation sequencing (NGS) panel in our laboratory during the period of 1 September 2021 to 31 August 2022 for the newborn screening (NBS) of six conditions for inborn errors of metabolism: citrullinemia type II (MIM #605814), systemic primary carnitine deficiency (MIM #212140), glutaric acidemia type I (MIM #231670), beta-ketothiolase deficiency (#203750), holocarboxylase synthetase deficiency (MIM #253270) and 3-hydroxy-3-methylglutaryl-CoA lyase deficiency (MIM # 246450). The custom-designed NGS panel can detect sequence variants in the relevant genes and also specifically screen for the presence of the hotspot variant IVS16ins3kb of by the copy number variant calling algorithm. Genetic second-tier tests were performed for 1.

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A three-year-old Chinese girl presented with hyperammonemia was diagnosed biochemically and genetically (heterozygous for a novel likely pathogenic missense variant c.476T>A) as having ornithine transcarbamylase (OTC) deficiency, a rare X-linked recessive urea cycle disorders. Extensive family genetic screening eventually revealed paternal gonadosomatic mosaicism.

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Article Synopsis
  • - Familial hCG syndrome is a rare condition that causes high levels of beta human chorionic gonadotropin (hCG) in the blood, and the case discussed is the first documented instance in a Chinese family.
  • - A 38-year-old woman had persistently elevated hCG levels discovered incidentally, which were verified through both urine and blood tests, with no signs of pregnancy or cancer found during thorough medical investigations.
  • - Further testing of a symptom-free family member showed elevated hCG levels as well, helping to confirm the familial nature of the syndrome, highlighting the need for clinicians to be aware of this condition to prevent unnecessary tests and treatments.
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Article Synopsis
  • Tuberculous meningitis (TBM) is a serious infection that requires quick diagnosis and treatment, highlighting the need for an efficient lab test to distinguish it from other conditions.
  • A study was conducted on 51 patients over three years, where CSF-ADA activity was measured, showing it was significantly higher in patients diagnosed with TBM compared to those with other types of meningitis.
  • The optimal CSF-ADA cut-off for diagnosing TBM was found to be 5.1 U/L, demonstrating high sensitivity and specificity, making it a reliable and fast method for distinguishing TBM and allowing for timely treatment.
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