The frequency of genetic eye diseases in a genetic counseling center.

The frequency of genetic eye diseases in a genetic counseling center: In this study the incidence of eye diseases of genetic origin in patients attending our genetic counseling center for a period of almost six years is documented. The frequency of retinitis pigmentosa, congenital cataracts, lens dislocation, microphthalmos, retinoblastoma, congenital glaucoma, congenital ptosis, degenerative myopia, strabismus, optic atrophy, various genetic metabolic diseases have been investigated, and the results are presented. Preventive approaches and prenatal diagnostic possibilities are discussed and the importance of genetic counseling is emphasized.

First-trimester alpha-fetoprotein screening for Down syndrome.

Screening for Down syndrome and other chromosomal aneuploidies by biochemical parameters in maternal serum is well established for the second trimester. With screening as late as 16 weeks of gestation, the option of chorionic villus sampling (CVS) unfortunately is lost. In our study population, the maternal serum alpha-fetoprotein (MSAFP) concentration was determined in 2471 women in the first trimester immediately prior to CVS. Although in this sample MSAFP tended to be lower in Down syndrome (DS) pregnancies than in pregnancies with a chromosomally normal fetus, at this early gestational age neither a fixed cut-off level of 0.5 multiples of the normal median (MOM) nor one of 0.6 MOM was suitable for identifying pregnancies at higher risk for DS. This also applied to trisomy 18, although on average MSAFP in trisomy 18 pregnancies was lower than in normal and DS pregnancies.

Two cystic fibrosis patients with the genotype G542X/G551D.

Two adult sisters affected by cystic fibrosis were both shown to carry two different alterations within exon 11 of the CFTR gene, the nonsense mutation G542X and the missense mutation G551D. Both patients exhibit a relatively benign clinical course. In the described patients, G542X functions as a "mild" allele and is, in this respect, dominant to the "severe" G551D.

Brachy/ectrodactyly and absence or hypoplasia of the fibula: an autosomal dominant condition with low penetrance and variable expressivity.

A complex dysostosis characterized by brachy- and/or ectrodactyly and fibular hypoplasia was found in two distantly related individuals. The proposita, aged 25 years, showed metacarpal and phalangeal hypoplasia on both hands, ectrodactyly on both feet, and nearly complete bilateral absence of the fibula. Only milder acromelic defects were detected in a second cousin. A similar pattern of skeletal involvement had been previously described in an unrelated Italian family. The peculiar segregation pattern can be explained by autosomal dominant inheritance with low penetrance and variable expressivity.

[Occurrence of 3 primary carcinomas within 26 months]. / Auftreten dreier Primärkarzinome innerhalb von 26 Monaten.

One case of 3 primary malignant tumors is reported. Having undergone adjuvant polychemotherapy after mastectomy for cancer of the right breast, 2 more primary malignomas were found in a 73-year-old woman within 26 months: malignant melanoma for the right upper arm and scirrhous gastric cancer. Possible induction of secondary/tertiary neoplasms by polychemotherapy with alkylating drugs is discussed. The importance of early detection of secondary/tertiary malignancies and of their delimitation against metastases is underlined as being indispensable for the proper planning of adequate therapy.

First trimester maternal serum alpha-fetoprotein screening for Down syndrome and other aneuploidies.

Low maternal serum AFP (MSAFP) values in the first trimester of pregnancy have been associated with an increased risk for chromosome disorders. In our own first trimester chorionic villus sampling (CVS) series, MSAFP determinations were carried out in 1,448 singleton pregnancies. Aneuploidies were detected in 26 of these. The pre-CVS MSAFP values in these pregnancies were compared to those in pregnancies with normal outcome. Statistical analysis did not show a diagnostically useful correlation between low first trimester MSAFP values and aneuploidy in our cohort.

[Progress in prenatal diagnosis]. / Fortschritte der Pränataldiagnostik.

Prenatal diagnosis is primarily the task of the obstetrician and clinical geneticist, but it must concern the pediatrician as well. It may give advance warning of postnatal problems and yield information that is valuable in the care of the newborn. Moreover, the pediatrician may be called upon to judge the prognosis of a child with a prenatally detected anomaly and prenatal therapy might be considered. Recent progress in prenatal diagnosis concerns sonography, including fetal blood sampling and biopsy; early detection of neural tube defects by alpha-fetoprotein and acetylcholinesterase determination (ACHE test); first trimester diagnosis of chromosome anomalies and inborn errors of metabolism; and prenatal DNA analysis. Technical progress in prenatal diagnosis improves the reliability of prognosis and genetic counselling, but also adds to existing ethical problems and may create new ones.

[Important progress for the ophthalmologist in basic genetic research]. / Für den Augenarzt wichtige Fortschritte der genetischen Grundlagenforschung.

Ophthalmologists and human geneticists share a long standing interest in hereditary diseases and anomalies of the eye. Many of the primary genetic eye diseases are known, as ophthalmic symptoms are frequently part of a pleiotropic gene effect or the eye is affected secondarily. Progress in human genetics has also improved the understanding of genetic eye diseases. This can be demonstrated in the analysis of the function of color-vision genes and their abnormalities as well as the retinoblastoma gene. A line can be drawn from early formal analysis of pedigrees to cytogenetic mapping and, finally DNA analysis and sequencing of the involved genes. These advances have not only led to theoretical insights but also have practical applications where the determination of risk is concerned or prenatal diagnosis, genetic counselling, preventive measures and guidance. The retinoblastoma gene has become an important model for a tumor suppressor gene and tumorigenesis in general. Its influence on other types of tumors, such as osteosarcoma and breast cancer must be clarified. Sequencing of the gene opens the possibility of reconstructing the primary gene product by "reverse genetics" and of analyzing its mode of action. DNA analysis has been extended to an increasing number of eye diseases. Precise clinical and genetic analysis and diagnosis are of primary importance, however, for progress in this field.

Feto-maternal transfusion after chorionic villus sampling. Evaluation by maternal serum alphafetoprotein measurement.

The alphafetoprotein (AFP) concentration in maternal serum was determined before and after chorionic villus sampling (CVS). A significant increase of 20% or more in the pre-CVS level was noted immediately after sampling in 59% of 837 pregnancies indicating some degree of feto-maternal haemorrhage. The increase in the AFP concentration in maternal serum was correlated with the weight of the tissue sample but not with the number of sampling attempts. A correlation of AFP increase and frequency of spontaneous abortions following CVS was suggested only in the group with an AFP increase of more than 100% or with a continuing rise in the first hour following CVS. CVS in early pregnancy obviously did not interfere with maternal serum AFP screening for neural tube defects in the second trimester. Although AFP measurement before and after CVS seems to have no immediate diagnostic application, in the research phase of CVS it may help to identify those procedures that are the least traumatic.

[What should the pediatrician know about prenatal AFP diagnosis?]. / Was sollte der Pädiater über die pränatale AFP-Diagnostik wissen?

Alphafetoprotein (AFP) represents an embryo-fetal glycoprotein. The fetus it enters amnion fluid and maternal serum. Increased concentrations are observed in these fluids in the presence of certain fetal malformations, e.g. neural tube defects and anterior abdominal wall defects or omphalocele, and in congenital nephrosis of the Finnish type. An increased concentration also signals general risks as an increased tendency to abortion or to low birth weight infants. Very low maternal serum AFP indicates an increased risk for trisomy 21. Postnatally increased AFP-concentration has been described in ataxia-teleangiectasia (Louis-Bar-Syndrome) and in severe combined immunodeficiency syndrome. Although the AFP-determination is mainly used for obstetric prenatal care and diagnosis it also has an importance for the pediatrician as an early indicator of special risks.