No abstract

We report on a mildly abnormal 5-year-old girl with seizures, psychomotor retardation, and areas of hyperpigmentation who had a supernumerary marker chromosome in fibroblasts which was identified as an i(5p). To our knowledge, this is the first reported case of tetrasomy 5p. She shares in common some, but not all, manifestations of the dup (5p) syndrome. Cytogenetic analysis of relatives showed that the phenotypically apparently normal mother, maternal grandmother, and a brother of the proband also had a marker chromosome in their lymphocytes which was unrelated to the i(5p).

We report a case of Pallister-Killian syndrome initially diagnosed prenatally as tetrasomy 21. A 33-year-old primiparous woman was noted at 24 weeks' gestation to have moderate polyhydramnios. Ultrasonography showed diminished fetal stomach filling, hydronephrosis, and prominence of the cisterna magna. Cytogenetic analysis of cultured amniocytes was initially interpreted as mosaic tetrasomy 21: 46,XX/47,XX,+i(21q). The patient was then referred to our centre for genetic counselling. At 34 weeks' gestation, a dysmorphic infant was delivered and died within 30 min. Physical features were consistent with the Pallister-Killian syndrome. Renal, gastrointestinal, and central nervous system anomalies were found at post-mortem examination. Analysis of peripheral lymphocytes revealed 5 per cent of cells with a marker chromosome, while 92 per cent of cultured fibroblasts had this same marker. Fluorescent in situ hybridization (FISH) using an alpha-satellite probe for chromosomes 13 and 21 failed to hybridize to the marker, while a chromosome 12 centromeric probe unequivocally identified it as an i(12p). Use of FISH can provide rapid, specific prenatal diagnosis of ambiguous marker chromosomes and improve prenatal counselling.

The Atlantic bottlenose dolphin (Tursiops truncatus), a marine mammal found off the Atlantic coast, has become the focus of considerable attention because of an increasing number of mortality events witnessed in this species over the last several years along the southeastern United States. Assessment of the impact of environmental stressors on bottlenose dolphins (BND) has been difficult because of the protected status of these marine mammals. The studies presented herein focused on establishing epidermal cell cultures and cell lines as tools for the in vitro evaluation of environmental stressors on BND skin. Epidermal cell cultures were established from skin samples obtained from Atlantic BND and subjected to karyotype analysis. These cultures were further characterized using immunohistochemical methods demonstrating expression of cytokeratins. By two-dimensional polyacrylamide gel electrophoresis (2D-PAGE), we observed that the proteomic profile of BND skin tissue samples shared distinct similarities with that of skin-derived cultures. Epidermal cell cultures were transfected with a plasmid encoding the SV40 small t-and large T-antigens, as well as the neomycin-resistance gene. Five neomycin-resistant clones were isolated and expanded, and all of them proliferated at a faster rate than nontransfected BND epidermal cultures, which exhibited signs of senescence. Cell lysates prepared from two transfected clones were shown to express, by Western blot analysis, both SV40 tumor antigens. These experimental results are consistent with the concept that transfected clones expressing SV40 tumor antigens represent immortalized BND cell lines. Epidermal cell lines derived from Tursiops truncatus will provide a unique tool for studying key features of the interaction occurring between dolphins and the environment in which they live at their most crucial interface: the skin.