A fetus with multiple malformations was identified by prenatal ultrasound investigation. Cordocentesis and fetal lymphocyte chromosome analysis demonstrated a model number of 47 chromosomes. The extra chromosome material was identified as an isochromosome of the entire short arm of chromosome 9 with no involvement of the heterochromatic region of the long arm [47,XY, + i(9p)]. This represents the first report of prenatal diagnosis of tetrasomy 9p. Further delineation of the phenotype is discussed.

We describe five patients with tetrasomy 12p (one previously reported). These patients exhibit a very wide range of phenotypic features from that of classic Pallister‐Killian syndrome to only mild learning disabilities with pigmentary skin changes. As such, these cases highlight the fact that tetrasomy 12p [i(12p)] and Pallister‐Killian syndrome are not synonymous, although this combination of genotype and phenotype is often seen. This information is especially important in prenatally ascertained i(12p). The full spectrum of phenotypic possibilities associated with this chromosome aneuploidy should be discussed in prenatal counseling.

The study was carried out to determine the aetiological agent(s) associated with hydropericardium syndrome (Angara disease) in broilers in Pakistan. The results indicate that in addition to adenovirus some other agent is involved in causing the disease but that this agent requires co-infection by an adenovirus for the reproduction of the typical signs of the syndrome. The nature of this agent remains unknown because no discrete virus or virus-like particle could be seen by electron microscopy.

No abstract

Cleidocranial dysplasia (CCD) is an autosomal dominant skeletal dysplasia associated with cranial, clavicular, and dental anomalies. It is caused by mutations in the RUNX2 gene, which encodes an osteoblast-specific transcription factor and maps to chromosome 6p21. We report clinical and molecular cytogenetic studies in a patient with clinical features of CCD including wormian bones, delayed fontanel closure, hypoplastic clavicles and pubic rami, and supernumerary dentition. Additional abnormalities of bone growth and connective tissue, including easy bruisability, scarring, bleeding, joint hypermobility, and developmental delay were also observed. Molecular cytogenetic studies identified a de novo apparently balanced three-way translocation 46,XY,t(4;6;21)(p16;p21.1;q21). Further mapping revealed the breakpoint on 6p21 to be 50 kb upstream of exon 1 of the RUNX2 gene, with RUNX2 being intact on the derivative chromosome 6. We hypothesize that the proband's CCD has arisen from disruption of the developmentally regulated gene RUNX2 at the 6p21 breakpoint, due to a position effect mutation which may have altered the expression of the gene. Further studies might unravel a new regulatory element for RUNX2. ß