Publications by authors named "Ling-Yin Hung"

5 Publications

  • Page 1 of 1

X-chromosome inactivation and PCDH19-associated epileptic encephalopathy: A novel PCDH19 variant in a Chinese family.

Clin Chim Acta 2021 Oct 28;521:285-288. Epub 2021 Jul 28.

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

Background: Developmental and epileptic encephalopathy 9 (DEE9, MIM #300088) is an early onset seizure disorder associated with cognitive impairment and behavioral disturbances. It is caused by mutation in protocadherin 19 with an unusual X-linked inheritance selectively involving heterozygous females or mosaic hemizygous males, while hemizygous males are unaffected. Cellular interference was the postulated mechanism underlying the unusual inheritance pattern.

Case Report: We report a Chinese girl who presented with severe treatment refractory seizures at 26 months of age and was found heterozygous for a novel likely pathogenic missense variant NM_001184880.2:c.488T>A p.(Val163Glu) in PCDH19. Her younger sister, who was also heterozygous for the variant, was asymptomatic with normal development at the time of reporting at 37 months of age. X-chromosome inactivation study by androgen receptor gene methylation assay in DNA from peripheral leukocytes was performed which demonstrated somewhat skewed X-chromosome inactivation in the proband and extremely skewed X-chromosome inactivation in the asymptomatic younger sibling.

Conclusion: PCDH19-related seizure disorder has incomplete penetrance and variable expressivity. Further studies are required to determine the potential role of X-chromosome inactivation on the phenotypic variability and patient outcomes. Liberal referral for PCDH19 testing among female patients with early-onset seizures should be considered to enhance case detection.
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http://dx.doi.org/10.1016/j.cca.2021.07.023DOI Listing
October 2021

Case Report: The first familial hCG syndrome in a Chinese family.

F1000Res 2021 8;10:458. Epub 2021 Jun 8.

Chemical Pathology Laboratory, Department of Pathology, Queen Elizabeth Hospital, Kowloon, Hong Kong.

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.
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http://dx.doi.org/10.12688/f1000research.53636.1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8240598PMC
July 2021

Facial Puffiness in a 9-Year-Old Girl.

Clin Chem 2020 04;66(4):627-628

Department of Chemical Pathology, Prince of Wales Hospital, Shatin, Hong Kong SAR, China.

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http://dx.doi.org/10.1093/clinchem/hvaa006DOI Listing
April 2020

Clinical and pathological characterization of FLNC-related myofibrillar myopathy caused by founder variant c.8129G>A in Hong Kong Chinese.

Clin Genet 2020 05 23;97(5):747-757. Epub 2020 Feb 23.

Department of Pathology, Queen Elizabeth Hospital, Hong Kong.

FLNC-related myofibrillar myopathy could manifest as autosomal dominant late-onset slowly progressive proximal muscle weakness; involvements of cardiac and/or respiratory functions are common. We describe 34 patients in nine families of FLNC-related myofibrillar myopathy in Hong Kong ethnic Chinese diagnosed over the last 12 years, in whom the same pathogenic variant c.8129G>A (p.Trp2710*) was detected. Twenty-six patients were symptomatic when diagnosed; four patients died of pneumonia and/or respiratory failure. Abnormal amorphous material or granulofilamentous masses were detected in half of the cases, with mitochondrial abnormalities noted in two-thirds. We also show by haplotype analysis the founder effect associated with this Hong Kong variant, which might have occurred 42 to 71 generations ago or around Tang and Song dynasties, and underlain a higher incidence of myofibrillar myopathy among Hong Kong Chinese. The late-onset nature and slowly progressive course of the highly penetrant condition could have significant impact on the family members, and an early diagnosis could benefit the whole family. Considering another neighboring founder variant in FLNC in German patients, we advocate development of specific therapies such as chaperone-based or antisense oligonucleotide strategies for this particular type of myopathy.
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http://dx.doi.org/10.1111/cge.13715DOI Listing
May 2020

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
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