Molecular definition of the shortest region of deletion overlap in the Langer-Giedion syndrome.

The Langer-Giedion syndrome (LGS), which is characterized by craniofacial dysmorphism and skeletal abnormalities, is caused by a genetic defect in 8q24.1. We have used 13 anonymous DNA markers from an 8q24.1-specific microdissection library, as well as c-myc and thyroglobulin gene probes, to map the deletion breakpoints in 16 patients with LGS. Twelve patients had a cytogenetically visible deletion, two patients had an apparently balanced translocation, and two patients had an apparently normal karyotype. In all cases except one translocation patient, loss of genetic material was detected. The DNA markers fall into 10 deletion intervals. Clone L48 (D8S51) defines the shortest region of deletion overlap (SRO), which is estimated to be less than 2 Mbp. Three clones--p17-2.3 EE (D8S43), L24 (D8S45), and L40 (D8S49) - which flank the SRO recognize evolutionarily conserved sequences.

[13q syndrome--partial monosomy of the long arm of chromosome 13]. / Das 13q- Syndrom--Di partielle Monosomie für den distalen Abschnitt des langen Armes des Chromosom 13.

Examination of spontaneous abortions often reveals deletion 13q-. The authors report on a case of de novo deletion in a female newborn with karyotype 46,XX,del (13) (q33) and discuss the problems of the mapping of clinical syndromes. The critical part of the 13q- syndrome is presumably the band 13q33 and/or 13q34. In clinically suspicious cases chromosome visualization should be done with reliable methods (R-banding) in order to detect even very small defects. The gene localisation of esterase D is obviously proximal of the terminal part of chromosome 13.

[The analysis of chromosomes today: aspects of the technic with indications and importance of the method]. / Die Chromosomenanalyse heute: Aspekte zur Technik, Indikationsstellung und Bedeutung der Methode.

0.5 to 1% of all newborn possess a chromosomal aberration. In a growing number of neoplasias chromosomal disturbances become known. 10 years after the introduction of the band technique into cytogenetics this method must be regarded as most essential progress in the description of chromosomes. Apart from the exact identification of each individual chromosome the band technique allows the exact establishment of fraction points and gives the possibility of new progress in the gene tabulation. With the help of instances some of these possibilities are demonstrated. Prerequisite for the effective use of the analysis of chromosomes is a strong indication. An indication catalogue concerning the clinical application of the method summarizes the essential problems from paediatrics, gynaecology and internal medicine.

[Importance and trends of prenatal diagnostics]. / Bedeutung und Trends der pränatalen Diagnostik.

The prenatal diagnosis in the middle third of a pregnancy serves the purpose to avoid the birth of children with genetic defects. Its most important indications are: Age of the mother more than 38 years, previous birth of a child with chromosomal anomaly, birth of a child with defect of the neural tube or with biochemically diagnosable metabolic disease and the diagnosis of sex in X-chromosomal hereditary diseases. The amniocentesis necessary for this is performed in the 16th week of pregnancy. In cytogenetic problems the result is present, as a rule, within the following 2-3 weeks, whereas the biochemical diagnosis lasts somewhat longer depending on the growth of the cells. The task of the following years will be to shorten the times of diagnosis and to increase the number of prenatally recognizable genetic and genetically conditioned diseases, respectively.

Trisomy 9p resulting from de novo 9/15 translocation and a 9p isochromosome.

Trisomy 9p with de novo 9/15 translocation and 9p isochromosome was observed in a mentally defective boy with typical clinical features for this syndrome. This chromosomal aberration is probably caused by the pericentric inversion of chromosome 9 of the patient's father.