Silver-Russell syndrome in Hong Kong

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Multiple Xba I polymorphisms in Haemophilia A (I: Reply)

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A novel missense mutation in exon 4 of the factor VIII:C gene resulting in moderately severe hemophilia A

A new point mutation due to C → T transition at codon 189 (TCA) of the factor VIII:C gene was found in a Chinese patient with moderately severe hemophilia A. This mutation abolishers the EcoRI site (GAATTC) in exon 4 and can be directly detected by polyacrylamide gel electrophoresis of amplified genomic DNA.link_to_subscribed_fulltex

Thanatophoric Dysplasia Variant, San Diego Type in a Chinese Fetus, Caused by C746G Missense Mutation in FGFR3 Gene CP LEE

Abstract Thanatophoric dysplasia variant − San Diego type (TD-SD) is a variant of thanatophoric dysplasia (TD), sharing with TD subtype TD1, common mutations in the FGFR3 gene. We describe the first local case of TD-SD with missense mutation C746G in FGFR3 gene. Radiologically, major features consist of macrocephaly, wafer thin vertebral bodies, and metaphyseal flaring of tubular bones that differentiate from other types of thanatophoric dysplasia

Detecting exon deletions and duplications of the DMD gene using Multiplex Ligation-dependent Probe Amplification (MLPA)

Objectives: To evaluate the efficacy of Multiplex Ligation-dependent Probe Amplification (MLPA) technique in comparison with the traditional multiplex PCR assay in detection of exon deletions and duplications of the DMD gene. Design and methods: The sensitivity and accuracy of MLPA were assessed and compared with the multiplex PCR in a total of 63 subjects including 43 subjects with Duchenne muscular dystrophy (DMD) or Becker muscular dystrophy (BMD) and 20 female carriers. Results: MLPA was able to detect all the known deletions and duplications; it detected four additional mutations that had been missed by multiplex PCR. In addition, the extent of the deletions and duplications could be more accurately defined which in turn facilitated a genotype-phenotype correlation. Conclusions: MLPA is superior to multiplex PCR. It should be the method of choice for the detection of exon deletions and duplications of the DMD gene in patients with DMD or BMD, as well as in female carriers. © 2005 The Canadian Society of Clinical Chemists.link_to_subscribed_fulltex

Molecular defects in haemophilia B: Detection by direct restriction enzyme analysis

The common restriction fragment length polymorphisms (RFLPs) associated with the FIX gene: 5' BamH I, Dde I, BamH I (2), Taq I and 3' Hha I were absent or of low incidence in Southern Chinese and are therefore not useful for linkage analysis. No deletion was detected amongst seven consecutive unrelated haemophilia B patients, but one had an insertion of a 15 kb Pvu II fragment containing exon d. Using an alternate strategy of polymerase chain reaction (PCR) amplification and direct sequencing, the molecular defect in the other six patients was defined. The four novel mutations characterized were: nucleotide (nt) 6410 G→C (Gly 12→Ala); nt 31261 Δ T (stop codon 31 bp downstream); nt 31260 C→G (Thr 380→Ser) and nt 31122 C→A (Ala 34→Asp). Two patients had the same mutation at nt 6365, G→A (Arg -4→Gln), identical to one previously described in other ethnic groups, suggesting that this is a hotspot for mutation. Each of the mutations was found to affect an enzyme recognition site and could thus be identified by direct visualization of abnormal restriction fragments in amplified genomic DNA. This allows rapid and accurate DNA diagnosis of haemophilia B in an ethnic group which otherwise shows little or no polymorphism for the common RFLP sites.link_to_subscribed_fulltex

Thanatophoric dysplasia variant, San Diego type in a Chinese fetus, caused by C746G missense mutation in FGFR3 gene

Thanatophoric dysplasia variant - San Diego type (TD-SD) is a variant of thanatophoric dysplasia (TD), sharing with TD subtype TD1, common mutations in the FGFR3 gene. We describe the first local case of TD-SD with missense mutation C746G in FGFR3 gene. Radiologically, major features consist of macrocephaly, wafer thin vertebral bodies, and metaphyseal flaring of tubular bones that differentiate from other types of thanatophoric dysplasia.link_to_subscribed_fulltex

Metaphyseal chondrodysplasia McKusick type in a Chinese fetus, caused by novel compound heterozygosity 64T>A and 79G>T in RMRP gene

We present the first confirmed case by molecular analysis of a metaphyseal chondrodysplasia, McKusick type, in a 22-week fetus. Two novel compound heterozygous mutations, 64T>A and 79G>T, were found in the highly conserved regions of the RMRP gene. Twenty-two heterozygous g.1018 T>C mutations, two homozygous g.1018 T>C mutations, two heterozygous insertion mutations g.799_g.800insC and one heterozygous insertion mutation g.849_g.850insT were found among 100 normal controls. Careful radiological examination of the fetus for skeletal dysplasia allowed definitive diagnosis, proper genetic counselling and future prenatal diagnosis. Copyright © 2006 John Wiley & Sons. Ltd.link_to_subscribed_fulltex

Two cases of spondylothoracic dysostosis (Jarcho Levin syndrome) in Chinese population

Theme: Advances in Genetics and Genomics - Opportunities for the Asia-Pacific Regio