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Recent developments in the epitaxial growth of metallic and semiconducting silicides on silicon are reviewed. The structural, electronic and electrical properties of these silicide-silicon interfaces are examined with the aid of results obtained with a large variety of in-situ and ex-situ surface techniques. The paper will focus on two topics: (i) recent progress on the epitaxial growth of thin metallic CoSi2films on Si(111), (ii) epitaxial growth of thin semiconducting β-FeSi2films on Si(111), (100) and (100) vicinal faces.

Glial cell line-derived neurotrophic factor (Gdnf) and its alpha receptor (Gfra1) interact with the Ret receptor triggering its tyrosine kinase activity. As Gdnf and Ret have been linked to the development of Hirschsprung disease (HSCR), it seems likely that Gfra1could also be a susceptibility gene for HSCR. A further HSCR candidate gene is represented by the human homologue of the Dom (Dominant megacolon) mouse mutation, mapped to Chr 15, for which the gene has not yet been identified. In order to test if Gfra1 could be the Dom gene or if it represents a new possible HSCR locus we have undertaken the mapping of the mouse Gfra1. Using specific PCR primers on a somatic cell hybrid mapping panel and fluorescence in situ hybridization with an expressed sequence tag (EST) cDNA clone corresponding to the mouse Gfra1, we mapped the gene to mouse chromosome 19D2-D3, a region with known homology with human chromosome 10q24→q26.

We have identified a novel human gene with strong homology to the mouse Pa2g4 cell cycle gene. This novel gene (called PA2G4) belongs to a gene family with members in several chromosome regions: 3q24-q25, 6q22, 9q21, 12q13, 18q12, 20p12 and Xq25. A composite cDNA of 1697 nucleotides was isolated. The sequence of this cDNA predicts a protein of 394 amino acids. The deduced amino acid sequence of this human protein shows very strong homology to the mouse protein p38–2G4. The cDNA analyzed probably corresponds to a functional copy found at 12q13.

We report a female patient with a 46,XX,der(8)t(1;8)(q42.1;p23.3) karyotype who had a mild phenotype characterised by a few subtle dysmorphic features and mild developmental retardation, probably resulting from trisomy 1q42→qter. The deletion on the short arm of the chromosome 8 appeared to be confined to the distal chromosomal segment.

A centric fission of chromosome 9 was found in a boy with trisomy 9p resulting from a de novo del (9p) and a 9p isochromosome. The patient presented with clinical findings similar to those described in previously reported cases of trisomy 9p. The cytogenetic evaluation and the molecular analysis using fluorescence in situ hybridization (FISH) with specific alphoid probe for chromosome 9 showed a karyotype of 47,XY,+del(9)(q10),+i(9p). We suggest that the mechanism leading to this situation is unusual. Am. J. Med. Genet. 79:35–37, 1998. © 1998 Wiley-Liss, Inc.