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A 6-year-old girl is described with a unique, rare type of tibial hemimelia known as Carraro syndrome (OIMI 275230). There are only two previous reports of this condition in the literature. In our patient, the tibia anomaly was associated with other skeletal abnormalities, hemivertebra and tetralogy of Fallot. This association of malformations has not previously been reported. We conclude that this girl has either a variant of Carraro syndrome or a new syndrome.

We report on two siblings with a severe neonatal form of spondylometaphyseal dysplasia (SMD). Similar cases have been reported in four publications. Analysis of pedigree data from the original and present families suggests an autosomal recessive mode of inheritance, although parental gonadal mosaicism is also possible. The similarities in the phenotype between our patients and spondyloepimetaphyseal dysplasia congenita (SEMDC) and spondyloepimetaphyseal dysplasia Strudwick (SEMDS) type, indicated that these patients could have a defect in the COL2A1 gene. Molecular analysis of genomic DNA of these patients excluded this gene. Another potential candidate gene PTHR1, was also analyzed in the selected regions and no mutation was found. This gene is probably causative in the Jansen type of SMD, which shares some phenotypic features with the siblings whom we documented. Our results indicate that a new candidate gene for the reported form of SMD should be sought.

Reactions between ReH(7)(PPh(3))(2) and a series of benzylic imines, PhCHNR (R = Me, Ph, or Bn), produce the compounds ReH(4)[eta(2)-(1,2-C(6)H(4))CHNR](PPh(3))(2). One such compound, ReH(4)[eta(2)-(1,2-C(6)H(4))CHNPh](PPh(3))(2), was characterized by X-ray diffraction analysis. The compound ReH(4)[eta(2)-(1,2-C(6)H(4))CHNPh](PPh(3))(2) crystallizes in the P(&onemacr;) space group with the following unit cell dimensions: a = 12.422(3) Å, b = 12.696(3) Å, c = 13.604(5) Å, alpha = 93.26(2) degrees, beta = 90.66(2) degrees, gamma = 107.03(2) degrees, V = 2047.2 Å(3), and Z = 2. The structure was refined to R(F(o)) = 0.029 (R(w)(F(o)) = 0.034) for 5352 data with I > 3.0sigma(I). The structure determination indicates that ortho-metalation of the imine reactant occurs during the reaction of ReH(7)(PPh(3))(2) with PhCHNPh. The observation of four nu(Re-H) absorptions in the infrared spectrum of each ReH(4)[eta(2)-(1,2-C(6)H(4))CHNR](PPh(3))(2) compound indicates that the rhenium-bound hydrogen atoms, in these compounds, are better regarded as classical hydride ligands rather than as elongated dihydrogen ligands. Acidolysis reactions of the compounds ReH(4)[eta(2)-(1,2-C(6)H(4))CHNR](PPh(3))(2), with HBF(4).Et(2)O in acetonitrile, result in loss of the ortho-metalated imine ligands from the rhenium coordination spheres and in reduction of the imine functional groups to secondary ammonium cations. One hydride ligand is transferred to the imine carbon atom, during the course of each acidolysis reaction.