PCR in the Analysis of Clinical Samples: Prenatal and Postnatal Diagnosis of Inborn Errors of Metabolism.

Inborn errors of metabolism (IEMs) are individually rare but collectively common. As more and more genes are cloned and specific disease-causing mutations are identified, the diagnosis of IEMs is becoming increasingly confirmed by mutation analysis. Diagnosis is important not only for treatment and prognosis but also for genetic counselling and prenatal diagnosis in subsequent pregnancies. A wide range of molecular methods is available for the identification of mutations and other DNA variants, most of which are based on the Polymerase Chain Reaction (PCR). In this chapter, we focus on PCR-based methods for the detection of point mutations or small deletions/insertions as these are the most frequent causes of IEMs.

Prenatal detection of skeletal dysplasia using ultrasound and molecular diagnosis / 대한산부인과학회지

OBJECTIVE: To determine the accuracy and usefulness of prenatal ultrasonographic and molecular genetic diagnosis in detection of skeletal dysplasia. METHODS: This study was based upon data of the 17 cases of skeletal dysplasia diagnosed by prenatal ultrasound and 7 cases by molecular diagnosis performed among the 17 cases and the 2 cases who has familial skeletal dysplasia by molecular diagnosis during the first trimester at Ewha and Eulji University from March 1998 to August 2005. A final diagnosis was sought on the basis of radiographic studies, molecular testing, or both. RESULTS: The mean gestational age at diagnosis was 24.9 weeks (range, 17 to 35 weeks). Nine cases were diagnosed before 24 weeks. A final diagnosis was obtained in 16 cases (94.1%). There was 1 false-positive diagnosis. The antenatal diagnosis was correct in 14 cases (82.4%). The 8 cases were prenatally confirmed and 1 case was postpartum confirmed using molecular genetic testing and accurate antenatal diagnosis and prediction was done. We were able to rule out skeletal dysplasia through chorionic villus sampling during the first trimester in the 2 cases with the family history with skeletal dysplasia. CONCLUSION: Prenatal diagnosis of skeletal dysplasia can be a considerable diagnostic challenge. However, skeletal dysplasia is correctly diagnosed on the basis of prenatal meticulous ultrasound and antenatal prediction of lethality was highly accurate. Using prenatal molecular diagnosis, skeletal dysplasia can be diagnosed at first trimester of pregnancy and nonlethal skeletal dysplasia can be confirmed when prenatal ultrasound was nonspecific.

Prenatal Ultrasonographic and Molecular Diagnosis of Apert Syndrome: A case report / 대한산부인과학회지

Apert Syndrome is a kind of developmental disorder characterized by the craniosynostosis by synostosis of the coronal suture, bilateral symmetric syndactyly of the limbs (mitten-like hands and feet), midfacial hypoplasia, and variable degree of mental retardation. In 1894, Wheaton did the first description, and in 1906, it was named by Apert. Apert Syndrome is a rare autosomal dominent disorder and the prevalance at birth is estimated from 1:100000 to 160000. This syndrome is developed by the result of a mutation in the fibroblast growth factor receptor 2 gene (FGFR 2) located at 10q25.3-26. In familial cases, diagnosis in the first trimester sometimes has been made. But In sporadic cases, mostly it has been diagnosed in the second or third trimester by ultrasonography. In Korea, Apert syndrome is so rare, and it has not yet been reported that Apert syndrome is defined by prenatal molecular diagnosis with ultrasonographic detection. We present a case of prenatal molecular definitive diagnosis of Apert syndrome suspected strongly by ultrasonographic finding with a brief review of literature. Mother of affected fetus was transferred to our hospital at 31(2) weeks' gestation due to abnormal fetal ultrasound finding of severe polyhydroamnios and bilateral syndactyly of hands detected at 26(3) weeks' gestation. We suspected Apert syndrome by fetal ultrasonographic finding, and then confirmed Apert syndrome by DNA analysis of fetal amniocyte from therapeutic amnioredution at 31(4) weeks' gestation.

Prenatal molecular diagnosis of two pregnancies in familial G504S mutation of COL2A1 gene resulting spondylepiphyseal dysplasia congenita / 临床检验杂志

Objective To report the prenatal molecular diagnosis for two gravida in a family with spondylepiphyseal dysplasia congenita(SEDC)caused by G504S mutation of COL2A1 gene.Methods DNA of the two fetuses was extracted from amniotic fluid at the 19+3 and 18+6 weeks of gestation respectively.Direct sequencing of two samples were performed after amplifying exon 23 of COL2A1 containing the potential mutation.The femur length and biparietal diameter of the first fetus were measured by sonographic scans every two weeks from 17+3 weeks to 27+3 weeks of gestation,and for the second fetus these parameters were measured from 16+1 to 19+1 weeks of gestation.Results Sequncing analysis revealed the first fetus and his mother presented the same mutation which is specifically associated with SEDC,but the second fetus did not show the mutation of COL2A1 gene.Biparietal diameters of the both fetuses were appropriate for gestational age.Femur length of the second fetus was normal for gestational age but that of the first fetus was shortened evidently after the 23 week of gestation.The parents of the first fetus determined to terminate the pregnancy.A medical termination was carried out at 27+5 weeks of gestation and a male fetus with a relatively large head and short limbs was delivered.The radiological findings of the fetus were consistent with SEDC including generalized platy spondesand shortened long bones.Conclusions Prenatal molecular diagnosis is important for the fetus with risk of SEDC and useful for genetic counseling.Genotype of fetus with risk of SEDC can be identified before sonographic scan.Molecular genetic analysis in conjunction with sonographic monitoring was helpful in prenatal diagnosis of SEDC.