[Rapid prenatal genetic diagnosis of a fetus with a high risk for Morquio A syndrome].

OBJECTIVE: To provide rapid and accurate prenatal genetic diagnosis for a fetus with high risk of Morquio A syndrome. METHODS: Based on ascertained etiology of the proband and genotypes of the parents, particular mutations of the GALNS gene were screened at 10th gestational week with amplification refractory mutation system (ARMS), denaturing high performance liquid chromatography (DHPLC), and direct DNA sequencing. RESULTS: DHPLC screening has identified abnormal double peaks in the PCR products of exons 1 and 10, whilst only a single peak was detected in normal controls. Amplification of ARMS specific primers derived a specific product for the fetus's gene, whilst no similar product was detected in normal controls. Sequencing of PCR products confirmed that exons 1 and 10 of the GALNS gene from the fetus contained a heterozygous paternal c.106-111 del (p.L36-L37 del) deletion and a heterozygous maternal c.1097 T>C (p.L366P) missense mutation, which resulted in a compound heterozygote status. CONCLUSION: The fetus was diagnosed with Morquio A syndrome and a genotype similar to the proband. Termination of the pregnancy was recommended. Combined ARMS, DHPLC and DNA sequencing are effective for rapid and accurate prenatal diagnosis for fetus with a high risk for Morquio A syndrome. Such methods are particularly suitable for early diagnosis when pathogenesis is clear. Furthermore, combined ARMS and DHPLC are suitable for rapid processing of large numbers of samples for the identification of new mutations.

[Studies on safety of cordocentesis guided by transabdominal ultrasound for prenatal diagnosis].

OBJECTIVE: To assess the safety and efficacy of diagnostic cordocentesis during pregnancy. METHODS: During March 1990 to June 2003, 2403 consecutive cordocenteses were performed under transabdominal ultrasound guidance at Guangzhou Women and Children's Hospital. The results of each procedure was prospectively collected and subsequently analysed in terms of operational complications and pregnancy outcomes. RESULTS: Success rate of cordocentesis: totally 2368 procedures (98.5%) were done successfully at the first attempt, and 35(1.5%) required repeated cordocentesis, 16 of which were performed successfully at second attempt. Duration of cordocentesis: In 75.5% cases, the procedure was completed in less than 5 min, and in 93.0% cases in less than 10 min. COMPLICATIONS: Transient bleeding at puncture site was observed in 315 cases (13.1%), transient fetal bradycardia in 125 cases (5.2%), and chorioamnionitis in 2 cases (0.1%). Pregnancy outcomes: The total fetal loss rate was 0.8% (18 cases of abortions). The rate of premature birth after cordocentesis was 0.2% (4 cases). CONCLUSION: Cordocentesis during pregnancy is a useful, relatively safe, and effective procedure for prenatal diagnosis.