Rapid FMR1-protein analysis of fetal blood: an enhancement of prenatal diagnostics.

Fragile-X syndrome, a frequent cause of inherited mental retardation, is characterised in almost all cases by a CGG-repeat expansion that is located within the FMR-1 gene and that prevents the expression of fragile-X mental retardation protein (FMRP). We describe a test that simultaneously allows the rapid detection of FMRP in fetal lymphocytes and distinguishes these from fetal erythrocytes. Routine molecular genetic methods fail in the rare cases where protein expression is blocked, although there is no repeat expansion. Furthermore, they are unsuitable in cases of advanced pregnancy. Our test proves extremely valuable under both these circumstances.

Assessment of serum levels of alpha-1-microglobulin, beta-2-microglobulin, and retinol binding protein in the fetal blood. A method for prenatal evaluation of renal function.

The concentrations of alpha-1-microglobulin, beta-2-microglobulin, and retinol binding protein were determined in fetal blood sampled by cordocentesis. The blood values of 126 fetuses without ultrasonographic findings of urinary tract abnormalities as controls were found to be independent of the week of gestation. In nine fetuses affected by a severe bilateral renal dysplasia or agenesis, elevated values of alpha-1-microglobulin but normal values of retinol binding protein were obtained. The authors recommend the determination of alpha-1-microglobulin and, with some restriction, also of beta-2-microglobulin in prenatal renal function diagnosis.

[Cystic kidney dysplasia of variable expression--prenatal ultrasound, cytogenetic and patho-anatomic findings based on 3 case examples]. / Zystische Nierendysplasie variabler Ausprägung--Pränatal-sonographische, zytogenetische und patho-anatomische Befunde anhand von drei Fallbeispielen.

The present study reports on 3 cases of cystic renal dysplasias of Potter II type with variable characteristics and different clinical symptoms. The prenatal sonography revealed multicystically altered kidneys in the 19th to 33 rd week of gestation. Amniotic fluid cells and fetale lymphocytes were investigated to exclude possible chromosomal disorders. In case one, a unilateral cystic renal dysplasia was diagnosed by sonography in the 19th week of gestation. The chromosome analysis revealed one additional and altered chromosome 22 (partial trisomy). In case two, a bilateral cystic renal disease with oligohydramnios was distinguished in week 21 of gestation. In both cases, the pregnancies underwent artificial abortions and the stillborn infants were subjected to post mortem examinations. The patho-anatomical examinations confirmed the results of prenatal diagnoses and the classification of the cystic renal alteration as renal dysplasia of Potter II type. In case two, extrarenal malformations were found additionally. In case three, sonography revealed a unilateral multicystic kidney. In this case, there had not been any clinical symptoms in the prenatal stage, neither originating from the affected organ nor from other disorders. After delivery at predicted day a unilateral nephrectomy was performed because of space-consuming growth inside the abdominal cavity.

[Partial monosomy 21 or fetal alcohol embryopathy in a retarded boy?]. / Partielle Monosomie 21 oder Alkoholembryofetopathie bei einem retardierten Knaben?

A male newborn showed dysmorphisms combined with a complex cerebral malformation and a growth retardation. Alcohol damage in utero was suspected to be the cause. A deletion 21q (mosaic) was found in the karyotype.

[Dietary management of phenylketonuria patients using a personal computer]. / Diätführung von Phenylketonurie-Patienten über einen Personal-Computer.

The communication between the responsible physician and the family of the phenylketonuric patient requires an extended period of time in the treatment centre. Computer software was developed for the centre to ensure individual treatment of all patients according to the dietary recommendations. The program is additionally able to document all clinical data and to handle the correspondence with the family of the patient.

Cu/Zn superoxide dismutase quantification from fetal erythrocytes--an efficient confirmatory test for Down's syndrome after maternal serum screening and sonographic investigations.

An enzyme immunoassay especially designed for the quantification of Cu/Zn superoxide dismutase (SOD) in erythrocytes has been applied to measure the SOD of outcomes with high risk for Down's syndrome. From 148 fetuses SOD was quantified from erythrocytes of umbilical vein blood and related to the number of cells, the content of haemoglobin (Hb), and to the haematocrit (Hc). Comparative studies between the SOD content of erythrocytes from the fetuses and their mothers resulted in similar SOD levels (14.09 +/- 1.20 for fetal and 14.48 +/- 1.63 for maternal cells) with a 1.84-fold smaller variance for fetal cells. The best differentiation between normal fetuses and fetuses with Down's syndrome resulted from the SOD/cell ratio followed by the SOD/Hb ratio. Fixing a cut-off value from the probability density functions that the method results in a specificity of 99.99 per cent, the sensitivity to detect cases of Down's syndrome was 99.71 per cent for the SOD/cell ratio, 70.92 per cent for the SOD/Hb ratio, and 60.21 per cent for the SOD/He ratio. Nine cases with Down's syndrome were correctly diagnosed by the SOD/cell ratio determination. Eight of these were confirmed as free trisomy 21 by karyotype analysis and one was found to be a triploidy. The latter was not detected by the SOD/Hb and SOD/Hc ratios because of the one-third higher content of haemoglobin and the larger volume of the erythrocytes which resulted in ratios within the normal range.

Immunochemical quantification of Cu/Zn superoxide dismutase in prenatal diagnosis of Down's syndrome.

Cu/Zn superoxide dismutase (SOD) was quantified by enzyme immunoassay for prenatal diagnosis of Down's syndrome. Overall, 154 samples of amniotic fluid, 72 samples of amniotic cells and 31 samples of chorionic tissue were investigated. Due to the large biological variance of the SOD concentrations in normal pregnancies (range for amniotic fluid 10.5-154.9, for amniotic cells 40.0-338.8, and for chorionic tissue 132.2-649.5 g SOD/g protein) the cases of Down's syndrome detected by karyotype analysis were not reliably identified by Cu/Zn SOD quantification. As in erythrocytes obtained from patients with Down's syndrome, a trisomy 21 was easily and accurately detected in the erythrocytes from very small quantities (about 50 microliters) of umbilical blood. The SOD concentrations in normal cases (n = 40) varied between 11.4 and 17.3 and in the cases of trisomy 21, as confirmed by karyotyping (n = 4), between 22.5 and 23.2 ng/one million cells. SOD quantification in fetal erythrocyte is a helpful additional method in prenatal Down syndrome diagnosis under certain conditions, which are discussed.

[Biotinidase deficiency--a progressive metabolic disease in children with seizures and ataxia]. / Der Biotinidasemangel--Eine progrediente Stoffwechselerkrankung des Kindesalter mit Krampfanfällen und Ataxie.

Biotinidase deficiency is the primary biochemical defect in late-onset multiple carboxylase deficiency and an autosomal recessive disorder and characterized by seizures, ataxia, alopecia and skin rash. We describe a colorimetric semiquantitative method for screening for biotinidase activity from dried samples of whole blood spotted on filter papers. The administration of biotin to affected children can be a lifesaving procedure and can prevent irreversible neurologic damage.

[A staged plan for laboratory diagnosis of hereditary metabolic diseases]. / Stufenplan zur Labordiagnostik hereditärer Stoffwechselerkrankungen.

When clinical evidence provides grounds for suspecting inborn errors of metabolism it is urgent to perform the necessary, relevant, specific laboratory investigations in good time and with a view to quality. Normally, the realization depends on individual initiatives and the use of laboratories mainly designed for pediatrics and human genetics. Consequently the results are equally a matter of chance. Nothing in this situation can be changed in principle by using the catalogue of services of the Society for Human Genetics of the GDR. Central administrative provisions are necessary to improve the present unsatisfactory situation. Proposals for regulations, division of responsibility and a graduated programme of parameters are discussed here with a view to establishing uniform procedures.

Linkage disequilibrium between RFLP haplotype 2 and the affected PAH allele in PKU families from the Berlin area of the German Democratic Republic.

Probands from 26 PKU-affected families of the Berlin area were analyzed with respect to the allele frequency distribution of six RFLPs in linkage with the normal and the PKU alleles of the phenylalanine hydroxylase gene. These investigations confirm most of the RFLP haplotypes observed by Güttler and colleagues in the Danish population and describe two additional ones. They detect no significant differences in the single RFLP or RFLP haplotype distribution on the normal chromosomes in comparison with the Danish families and confirm a prevalent association of the RFLP haplotypes 1, 4, and 7 with the normal PAH allele. In contrast to the Danish investigations, in our study the PKU allele is found most frequently linked to haplotype 2, rather then to haplotype 3. In one of our patients we found a substitution of the normal 19-kb MspI fragment by a 13.5- and a 5.5-kb fragment, reported up to now only in one other German family.

Introduction of genomic diagnosis of classical phenylketonuria to the health care system of the German Democratic Republic.

The phenylketonuria (PKU) dispensary of the Children's Hospital of the Charité, Berlin, GDR, cares for about 140 affected families, representing about one-third of all PKU families in the GDR. Of these families, 15 expressed their desire for an additional child given the availability of a reasonably reliable prenatal diagnosis procedure. They were investigated by linked RFLP analysis applying a phenylalanine-hydroxylase-cDNA probe. Full genetic predictability for prospective fetuses could be obtained for all of them. In eight cases this was possible by the use of one restriction enzyme, and in the remaining seven by a combination of the information from two restriction-enzyme patterns. No recombination between linked RFLP and the PKU phenotype could be observed in 40 meioses from the investigation of eight families with two affected children each.

Prenatal diagnosis of classical phenylketonuria by linked restriction fragment length polymorphism analysis.

Since the isolation of a recombinant containing a cDNA sequence for human phenylalanine hydroxylase (hPH) (Woo et al., 1983; Speer et al., 1986) prenatal diagnosis by linked restriction fragment length polymorphism (RFLPs) has become possible for families in which phenylketonuria (PKU) occurs (Lidsky et al., 1985a). We describe here the application of a Hind III three-allele RFLP in a single family, which allowed the prenatal diagnosis of an affected fetus.

Typing of families with classical phenylketonuria using three alleles of the Hindiii linked restriction fragment polymorphism, detectable with a phenylalanine hydroxylase cDNA probe. Family typing for PKU by linked HindIII RFLP.

A human phenylalanine hydroxylase cDNA clone was isolated from a human liver cDNA library. The size of the cDNA insert is approximately 2.4 kb and appears to be a near full length copy of a phenylalanine hydroxylase mRNA. This cDNA was used to probe for HindIII restriction enzyme polymorphisms in heterozygote typing of families with phenylketonuria. The use of three alleles of this polymorphism, as opposed to the two alleles as previously described, increases the informativity for typing - and therefore also for prenatal diagnosis - in certain families from 75% to 100%.

[Resorption disorders in children with phenylketonuria]. / Resorptionsstörungen bei Kindern mit Phenylketonurie.

The usual loading test with D-xylose was carried out repeatedly in infants and toddlers with phenylketonuria. Significantly worse values of xylose resorption were found in comparison with healthy controls independent of the duration of the phenylalanine restricted diet. A further clearing for the matter of malabsorption in phenylketonuria seems to be recommendable with regard to secondary effects of the diet.

Creatine kinase isoenzyme BB in serum of healthy adults and children.

The activity of the creatine kinase isoenzyme BB was determined in the serum of 26 healthy adults and 31 children. The isoenzyme BB could be proved as a normal component in the human serum. In the adults examined, an activity of 0.56 +/- 0.16 I.U./l (x +/- S.D.) was determined. The activity of creatine kinase isoenzyme BB in the serum does not depend on sex but is subject, however, to a strong age dependence. Only at an age of more than 18 years, isoenzyme BB activities adjust to those of adults.