Expanded Newborn Screening for Inborn Errors of Metabolism in Hong Kong: Results and Outcome of a 7 Year Journey.

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.

A robust pipeline for ranking carrier frequencies of autosomal recessive and X-linked Mendelian disorders.

Single gene disorders are individually rare but collectively common leading causes of neonatal and pediatric morbidity and mortality. Both parents or the mothers of affected individuals with autosomal recessive or X-linked recessive diseases, respectively, are carrier(s). Carrier frequencies of recessive diseases can vary drastically among different ethnicities.

Investigation of Chromosomal Structural Abnormalities in Patients With Undiagnosed Neurodevelopmental Disorders.

Structural variations (SVs) are various types of the genomic rearrangements encompassing at least 50 nucleotides. These include unbalanced gains or losses of DNA segments (copy number changes, CNVs), balanced rearrangements (such as inversion or translocations), and complex combinations of several distinct rearrangements. SVs are known to play a significant role in contributing to human genomic disorders by disrupting the protein-coding genes or the interaction(s) with cis-regulatory elements.

ECNano: A cost-effective workflow for target enrichment sequencing and accurate variant calling on 4800 clinically significant genes using a single MinION flowcell.

Background: The application of long-read sequencing using the Oxford Nanopore Technologies (ONT) MinION sequencer is getting more diverse in the medical field. Having a high sequencing error of ONT and limited throughput from a single MinION flowcell, however, limits its applicability for accurate variant detection. Medical exome sequencing (MES) targets clinically significant exon regions, allowing rapid and comprehensive screening of pathogenic variants.

HKG: an open genetic variant database of 205 Hong Kong cantonese exomes.

HKG is the first fully accessible variant database for Hong Kong Cantonese, constructed from 205 novel whole-exome sequencing data. There has long been a research gap in the understanding of the genetic architecture of southern Chinese subgroups, including Hong Kong Cantonese. HKG detected 196 325 high-quality variants with 5.

CTNNB1-related neurodevelopmental disorder in a Chinese population: A case series.

CTNNB1-related disorder is an autosomal dominant neurodevelopmental disorder characterized by a variable degree of cognitive impairment, microcephaly, truncal hypotonia, peripheral spasticity, visual defects, and dysmorphic features. In this case series, we report the clinical and molecular findings of nine Chinese patients affected by CTNNB1-related disorders. The facial features of these affected individuals appear to resemble what had been previously described, with thin upper lip (77.

Further expanding the clinical phenotype in Bainbridge-Ropers syndrome and dissecting genotype-phenotype correlation in the ASXL3 mutational cluster regions.

Bainbridge-Ropers syndrome (BRPS) [OMIM#615485] is a neurodevelopmental disorder, characterized by delayed psychomotor development with generalized hypotonia, intellectual disability with poor or absent speech, feeding difficulties, growth failure, specific craniofacial and minor skeletal features. It was firstly reported in 2013 by Bainbridge et al., who observed a group of individuals sharing overlapping features with Bohring-Opitz syndrome which were caused by pathogenic variant in ASXL1, who indeed carried truncating mutations in ASXL3.

Prenatal and postnatal diagnosis of Schuurs-Hoeijmakers syndrome: Case series and review of the literature.

Schuurs-Hoeijmakers syndrome (SHS) is a rare syndrome involving a de novo variant in the PACS1 gene on chromosome 11q13. There are 36 individuals published in the literature so far, mostly diagnosed postnatally (34/36) after recognizing the typical facial features co-occurring with developmental delay, intellectual disability, and multiple malformations. Herein, we present one prenatal and 15 postnatal cases with the recurrent heterozygous pathogenic variant NM_018026.

Prenatal diagnosis and long-term follow-up of a Chinese patient with mosaic variegated aneuploidy and its molecular analysis.

Mosaic variegated aneuploidy (MVA) is a rare genetic disorder caused by mutations in , or . We describe the prenatal diagnosis, molecular characterization, and clinical management of a long-lived patient with -related MVA.

Identification of a PTEN mutation with reduced protein stability, phosphatase activity, and nuclear localization in Hong Kong patients with autistic features, neurodevelopmental delays, and macrocephaly.

PTEN is a tumor suppressor gene inactivated in over 30% of human cancers. It encodes a lipid phosphatase that serves as a gatekeeper of the phosphoinositide 3-kinase signaling pathway. Germline mutation frequently occurs in this gene in patients diagnosed with PTEN Hamartoma Tumor Syndrome (PHTS).

A report of three families with FBN1-related acromelic dysplasias and review of literature for genotype-phenotype correlation in geleophysic dysplasia.

Acromelic dysplasia is a heterogeneous group of rare skeletal dysplasias characterized by distal limb shortening. Weill-Marchesani syndrome (WMS), Geleophysic dysplasia (GD) and Acromicric dysplasia (AD) are clinically distinct entities within this group of disorders and are characterized by short stature, short hands, stiff joints, skin thickening, facial anomalies, normal intelligence and skeletal abnormalities. Mutations of the Fibrillin-1 (FBN1) gene have been reported to cause AD, GD and related phenotypes.

Performance of chromosomal microarray for patients with intellectual disabilities/developmental delay, autism, and multiple congenital anomalies in a Chinese cohort.

Background: Chromosomal microarray (CMA) is currently the first-tier genetic test for patients with idiopathic neuropsychiatric diseases in many countries. Its improved diagnostic yield over karyotyping and other molecular testing facilitates the identification of the underlying causes of neuropsychiatric diseases. In this study, we applied oligonucleotide array comparative genomic hybridization as the molecular genetic test in a Chinese cohort of children with DD/ID, autism or MCA.

A PTPN11 allele encoding a catalytically impaired SHP2 protein in a patient with a Noonan syndrome phenotype.

The RASopathies are a relatively common group of phenotypically similar and genetically related autosomal dominant genetic syndromes caused by missense mutations affecting genes participating in the RAS/mitogen-activated protein kinase (MAPK) pathway that include Noonan syndrome (NS) and Noonan syndrome with multiple lentigines (NSML, formerly LEOPARD syndrome). NS and NSML can be difficult to differentiate during infancy, but the presence of multiple lentigines, café au lait spots, and specific cardiac defects facilitate the diagnosis. Furthermore, individual PTPN11 missense mutations are highly specific to each syndrome and engender opposite biochemical alterations on the function of SHP-2, the protein product of that gene.

A different spectrum of DMD gene mutations in local Chinese patients with Duchenne/Becker muscular dystrophy.

Background: Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD) are X-linked recessive, allelic disorders. This study was conducted to look into the spectrum of DMD gene mutations in Hong Kong Chinese patients with Duchenne or Becker muscular dystrophy (DMD/BMD), and to study genotype-phenotype correlation.

Methods: A retrospective review of 67 patients.