Diagnostic pitfall in antenatal manifestations of CPT II deficiency.

Carnitine palmitoyltransferase II (CPT2) deficiency is a rare inborn error of mitochondrial fatty acid metabolism associated with various phenotypes. Whereas most patients present with postnatal signs of energetic failure affecting muscle and liver, a small subset of patients presents antenatal malformations including brain dysgenesis and neuronal migration defects. Here, we report recurrence of severe cerebral dysgenesis with Dandy-Walker malformation in three successive pregnancies and review previously reported antenatal cases. Interestingly, we also report that acylcarnitines profile, tested retrospectively on the amniotic fluid of last pregnancy, was not sensitive enough to allow reliable prenatal diagnosis of CPT2 deficiency. Finally, because fetuses affected by severe cerebral malformations are frequently aborted, CPT2 deficiency may be underestimated and fatty acid oxidation disorders should be considered when faced with a fetus with Dandy-Walker anomaly or another brain dysgenesis.

Hepatocyte transplantation using the domino concept in a child with tetrabiopterin nonresponsive phenylketonuria.

Phenylketonuria is a metabolic disease caused by phenylalanine hydroxylase deficiency. Treatment is based on a strict natural protein-restricted diet that is associated with the risk of malnutrition and severe psychosocial burden. Oral administration of tetrahydrobiopterin can increase residual enzyme activity, but most patients with severe clinical phenotypes are nonresponders. We performed liver cell transplantation in a 6-year-old boy with severe tetrahydrobiopterin nonresponsive phenylketonuria who failed to comply with diet prescriptions. The transplanted hepatocytes were obtained in part from an explanted glycogen storage type 1b liver. Following two infusions, blood phenylalanine levels returned within the therapeutic target while the phenylalanine half-life assessed by loading tests decreased from 43 to 19 h. However, 3 months later, blood phenylalanine concentrations increased and the phenylalanine intake had to be reduced. Cell-based therapy is a promising therapeutic option in phenylketonuria, and the domino concept may solve the issue of cell sources for hepatocyte transplantation.

Major decrease in the incidence of trisomy 21 at birth in south Belgium: mass impact of triple test?

In South Belgium (Wallonia), the 'triple test' was introduced in 1990-1991, and is nowadays a widely accepted screening method for assessment of trisomy 21 risk in pregnancy. The 'triple test' is not regulated and can be freely performed by any biomedical lab, making epidemiological data unavailable. By contrast, cytogenetic investigations are limited to a few genetic centres, and accurate statistics can be easily built from their files. During the period 1984-1989, a total of 244 trisomy 21 (1/876 pregnancies) were diagnosed in the Genetic Centres of Liège and Loverval, 42 (17%) of them prenatally. During the period 1993-1998, 294 trisomy 21 (1/704 pregnancies) were observed, 165 (56%) of which prenatally, and more than 90% of affected pregnancies were terminated. Even after correction for late foetal loss of trisomic foetuses, the difference is highly significant, and corresponds to a theoretical shift in the incidence of trisomy 21 at birth from 1/794 to 1/1606. As no remarkable progress occurred in other non-invasive prenatal screening procedures or general health care policies in Belgium, the most reasonable explanation is the use on a large scale of triple test by pregnant women, and the election of termination for most affected pregnancies.

[Programs of systematic screening in neonatology. Pharmaco-economic aspects]. / Les programmes de dépistage systématique en néonatologie. Aspects pharmaco-économiques.

Systematic neonatal screening offers many advantages for the patients, its family and the community. The Genetic center of the University Hospital of Liège provides neonatal screening for the following diseases: phenylketonuria, congenital hypothyroidy, cystic fibrosis, alpha-1-antitrypsin, adrenal hyperplasia and biotinidase deficiency. On economical grounds, it is clear that the organisation of neonatal screening costs less to the community than the cost of the disease if diagnosis is made too late as to allow an alleviation, or even a total recovery, of the symptomatology.

A prenatal trisomy 21 screening program using alpha-fetoprotein, human chorionic gonadotropin, and free estriol assays on maternal dried blood.

OBJECTIVE: The feasibility of large-scale Down syndrome maternal screening with dried blood samples and nonradioactive methods was examined. STUDY DESIGN: A prospective observation study was performed on a nonselected population of 11,241 pregnant women sampled between January 1991 and September 1992, between 14 and 24 weeks' gestation (ultrasonographic scanning available for 91.6%), through a multicenter collaborative network. Enzyme-linked immunosorbent assays for alpha-fetoprotein, human chorionic gonadotropin, and free estriol were performed on dried blood samples. Risk determination was made with an in-house software implementing the multivariate gaussian log likelihood method. RESULTS: A total of 10,450 samples were eligible for the study. Mean age at term was 27.9 years. A total of 6.84% of the patients were > or = 35 years old with a prior risk of trisomy 21 > 1:350. The general positive rate of our sample was 8.15%. After calculation 31.7% with prior risk > 1:350 were still in the high-risk group; 6.36% of the low-risk group were found to be at high risk for Down syndrome. Fifteen trisomic pregnancies were observed, of which 11 had a calculated risk higher than the selected cutoff value (1:350). The overall detection rate was 73%, specificity was 92%, and positive predictive power was 1.2%. CONCLUSION: Our pilot study has shown performances within the range of conventional serum screening programs. Dried blood assays are a handy alternative to serum assays. Blot paper cards represent a simple method of sampling, well fitted for large population screening. Combined with nonradioactive methods, this method appears to be both low cost and effective. The current work apparently is the first large-scale Down screening program performed with dried blood.

Enzyme immunoassay screening of alpha 1-antitrypsin in dried blood spots from 39 289 newborns.

We present a new, simple, and inexpensive sandwich-type double-antibody enzyme immunoassay for alpha 1-antitrypsin in dried blood collected on the fifth day post-partum. The method is very sensitive, having a detection limit of 2.84 fmol/well. Intra- and interassay CVs are 6.1% and 10.3%, respectively, for assay of 5-mm-diameter blood spots eluted into 7 mL of phosphate buffer. Since February 1984, we have used this method to systematically screen 39 289 consecutive births: 336 of these newborns (0.085%) showed values for alpha 1-antitrypsin below the cutoff value of 800 mg/L (50th percentile, 1470 mg/L). Of these 336 we were able to obtain 0.5 mL of serum from 161 for further testing. Four presented with a ZZ phenotype and 15 with a SZ phenotype, which indicates a deficiency in alpha 1-antitrypsin. Our data suggest a prevalence of 1.4% and 3.6% of Z and S alleles, respectively, in the French-speaking community of Belgium.

[Hemoglobin A1c and diabetes control (author's transl)]. / Hémoglobine a1c et controle du diabète.

Hemoglobin A1c (HbA1c) is a minor component of human hemoglobin resulting from a non enzymatic linkage of glucose with the NH2-terminal amino acid of the beta chain of hemoglobin. Under normal conditions, HbA1c represent about 5% of total hemoglobin. The HbA1c blood concentration increases in direct proportion of the duration and degree of hyperglycemia. Available procedures for measuring HbA1c include column chromatography, high pressure liquid chromatography, a colorimetric procedure based on the formation of 5-hydroxymethylfurfural and isoelectrofocusing. In a group of 138 patients, we have confirmed that HbA1c provides a useful means of evaluating the degree of diabetic control: the highest values have been recorded in cases of poor control, the lowest in cases of excellent control. In the latter case, the HbA1c values recorded were not statistically different from those obtained in a control group of 92 non-diabetic subjects. The interest of evaluating this parameter in diabetes is briefly analyzed.

Dosage of hemoglobin A1c by isoelectrofocusing.

A new Hb A1c routine dosage method is proposed, using thin-layer isoelectrofocusing. The mean level in normal adults is 4.66% (sigma = 1.05). In diabetic (treated) patients, the distribution of Hb A1c levels is a non-Gaussian one, with extreme values of 3 to 13% and a maximum frequency peak at 5.5%.