For the purpose of prenatal diagnosis of CAH, genetic linkage analysis by HLA genotyping with lymphocytes and cultured amniotic cells were performed in a family at risk in which two consecutive children had been affected with SW CAH. In addition, the response of serum 17-OHP to intravenous ACTH was determined in obligate carrier parents, and 17-OHP concentration of amniotic fluid was also measured at 16 weeks of gestation. As might be expected, the baseline levels of 17-OHP in obligate parents were significantly higher than that of normal control. Although the post stimulation response of 17-OHP to ACTH in the mother (I-2) was significantly higher than that of normal control, the post stimulation levels of 17-OHP were in normal range in the father (I-1). The 17-OHP level (5.7 ng/ml) in the amniotic fluid showed intermediate value compared to Pang's report (normal less than 30 ng/ml, CAH greater than 12.0 ng/ml) suggesting heterozygote of the fetus. Genetic linkage analysis by HLA genotyping with cultured amniotic cells revealed heterozygote in their fetus (II-3) who has received one chromosome No,6 containing HLA haplotype A24, B40, Cw3 (normal allele for 21-OH) from the father and the other chromosome No,6 containing HLA haplotype A2, Bw62, Cw4 (mutant allele for 21-OH D) from the mother. In conclusion, attempts to detect heterozygote for 21-OH deficiency by ACTH stimulation test were partially successful and prenatal diagnosis of CAH by the hormone studies in ammiotic fluid requires reliable values in normal, heterozygotes and patients group, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
*Adrenal Hyperplasia, Congenital/*diagnosis/enzymology/genetics ; Adult ; Amniocentesis ; Cells, Cultured ; Female ; Fetal Diseases/*diagnosis/enzymology ; HLA Antigens/analysis ; Heterozygote Detection ; Humans ; Pedigree ; Pregnancy ; *Prenatal Diagnosis ; Steroid Hydroxylases

OBJECTIVETo characterize the mutation spectrum of phenylalanine hydroxylase (PAH) gene and perform prenatal diagnosis for families with classical phenylketonuria.

METHODSBy stratified sequencing, mutations were detected in the exons and flaking introns of PAH gene of 44 families with classical phenylketonuria. 47 fetuses were diagnosed by combined sequencing with linkage analysis of three common short tandem repeats (STR) (PAH-STR, PAH-26 and PAH-32) in the PAH gene.

RESULTSThirty-one types of mutations were identified. A total of 84 mutations were identified in 88 alleles (95.45%), in which the most common mutation have been R243Q (21.59%), EX6-96A>G (6.82%), IVS4-1G>A (5.86%) and IVS7+2T>A (5.86%). Most mutations were found in exons 3, 5, 6, 7, 11 and 12. The polymorphism information content (PIC) of these three STR markers was 0.71 (PAH-STR), 0.48 (PAH-26) and 0.40 (PAH-32), respectively. Prenatal diagnosis was performed successfully with the combined method in 47 fetuses of 44 classical phenylketonuria families. Among them, 11 (23.4%) were diagnosed as affected, 24 (51.1%) as carriers, and 12 (25.5%) as unaffected.

CONCLUSIONPrenatal diagnosis can be achieved efficiently and accurately by stratified sequencing of PAH gene and linkage analysis of STR for classical phenylketonuria families.

Adolescent ; Adult ; Case-Control Studies ; Child ; Child, Preschool ; Female ; Fetal Diseases ; diagnosis ; enzymology ; genetics ; Genetic Testing ; Humans ; Infant ; Infant, Newborn ; Male ; Microsatellite Repeats ; Middle Aged ; Pedigree ; Phenylalanine Hydroxylase ; genetics ; Phenylketonurias ; diagnosis ; enzymology ; genetics ; Point Mutation ; Pregnancy ; Prenatal Diagnosis ; Young Adult

OBJECTIVETo perform genotyping analysis and subsequent prenatal genetic diagnosis for two families affected with oculocutaneous albinism (OCA).

METHODSDirect sequencing of TYR and P genes was performed in two albino probands. Family members were screened for corresponding mutant alleles. Prenatal genetic diagnoses were performed at early pregnancy by chorionic villus sampling (CVS) at mid-pregnancy through amniocentesis.

RESULTSNo mutations were detected in the TYR gene in either probands, whereas 4 heterozygous mutations of the P gene were found, namely c.406C>T, c.535A>G, c.808-2A>G and c.2180T>C, among which c.535A>G and c.808-2A>G were novel. In the first round prenatal genetic testing, both fetuses were found to have the same genotypes as the probands. Both families had decided to terminate the pregnancy after genetic counseling. In the second round testing, neither of the fetuses was found to be affected by genotyping. The pregnancies continued and two healthy fetuses were born.

CONCLUSIONOCA can be classified by genotyping, with which reliable prenatal diagnosis and feasible genetic counseling may be provided.

Adolescent ; Adult ; Albinism, Oculocutaneous ; diagnosis ; embryology ; enzymology ; genetics ; Asian Continental Ancestry Group ; genetics ; Base Sequence ; Child ; Child, Preschool ; Female ; Fetal Diseases ; diagnosis ; genetics ; Genotype ; Humans ; Infant ; Male ; Membrane Transport Proteins ; genetics ; Middle Aged ; Molecular Sequence Data ; Monophenol Monooxygenase ; genetics ; Pedigree ; Point Mutation ; Pregnancy ; Prenatal Diagnosis ; Young Adult