Gertrud Dudin

A method for nucleic acid hybridization to isolated chromosomes in suspension

SummaryA procedure was developed to provide differential fluorescent staining of metaphase chromosomes in suspension following nucleic acid hybridization. For this purpose metaphase chromosomes were isolated from a Chinese hamster x human hybrid cell line. After hybridization with biotinylated human genomic DNA, the human chromosomes were visualized by indirect immunofluorescence using antibodies against biotin and fluoresceine-isothiocyanate-(FITC)-labeled second antibodies. This resulted in green fluorescent human chromosomes. In contrast, Chinese hamster chromosomes revealed red fluorescent staining only when counterstained with propidium iodide. Notably, interspecies chromosomal rearrangements could be easily detected. After hybridization and fluorescent staining, chromosomes still showed a well-preserved morphology under the light microscope. We suggest that this procedure may have a useful application in flow cytometry and sorting.

Sorting of chromosomes by magnetic separation

SummaryChromosomes were isolated from Chinese hamster x human hybrid cell lines containing four and nine human chromosomes. Human genomic DNA was biotinylated by nick translation and used to label the human chromosomes by in situ hybridization in suspension. Streptavidin was covalently coupled to the surface of magnetic beads and these were incubated with the hybridized chromosomes. The human chromosomes were bound to the magnetic beads through the strong biotin-streptavidin complex and then rapidly separated from nonlabeled Chinese hamster chromosomes by a simple permanent magnet. The hybridization was visualized by additional binding of avidin-FITC (fluorescein) to the unoccupied biotinylated human DNA bound to the human chromosomes. After magnetic separation, up to 98% of the individual chromosomes attached to magnetic beads were classified as human chromosomes by fluorescence microscopy.

Ehlers‐Danlos syndrome type IV D: an autosomal recessive disorder

Two siblings born to consanguineous parents are reported with typical clinical features of the Ehlers‐Danlos syndrome type IV. However, their cultured skin fibroblasts synthesize and secrete procollagen type III in normal amounts and proportions. This is probably a new form of the Ehlers‐Danlos syndrome with autosomal recessive inheritance classified as Ehlers‐Danlos syndrome type IV D.

Hereditary retinoblastoma and 13q--mosaicism.

Mosaicism for a 13q interstitial deletion was found in a minor fraction of peripheral blood lymphocytes in a 10-month-old girl affected with bilateral retinoblastoma. The tumor was inherited from the unilaterally affected father.

Interstitial deletion of band q12 of chromosome 5

A six‐months‐old girl is presented with psychomotor retardation and multiple congenital malformations. The karyotype done on peripheral blood lymphocytes and skin fibroblasts was found to be 46,XX del(5)(411q13). The parents are consanguineous. Their karyotypes were normal.

Eye findings in interstitial deletion of band q12 of chromosome 5

An 18-month-old girl presented with the ocular findings of severe ptosis of the right upper lid, astigmatism and the Adduction Fixation Preference. She also had psychomotor retardation and multiple congenital anomalies. The karyotype revealed an interstitial deletion of the long arm of chromosome 5 at q 12. This is the first description of the ophthalmological findings in this chromosomal disorder.

The association of Duane and Noonan syndromes Report of a case

The combination of the Duane retraction and the Noonan syndromes in a 12-year-old boy is reported for the first time.

The association of a fragile site on chromosome 10 with the Sturge-Weber syndrome and congenital glaucoma

A folic acid sensitive fragile site on chromosome 10q23 in a case of Sturge-Weber syndrome with unilateral glaucoma is described. The literature reporting such chromosomal fragile sites is reviewed, and the significance of this abnormality in relation with various congenital malformations is discussed.