Monosomy 1p36 is the most common terminal deletion syndrome. This contiguous gene deletion syndrome is presumably caused by haploinsufficiency of a number of genes. We have constructed a contig of overlapping large-insert clones for the most distal 10.5 Mb of 1p36, evaluated the deletion sizes in 61 subjects with monosomy 1p36 from 60 families, and created a natural deletion panel. We found pure terminal deletions, interstitial deletions, derivative chromosomes, and more complex rearrangements. Breakpoints were "binned" into 0.5-Mb regions. Analyses revealed some clustering of breakpoints but no single common breakpoint. Determination of the parental origin showed that 60% of de novo 1p36 terminal deletions arose from the maternally inherited chromosome. Of the 61 subjects, 30 were examined systematically through a protocol at the Texas Children's Hospital General Clinical Research Center. Specifically, we report hearing evaluations, palatal and ophthalmological examinations, echocardiograms, neurological assessments, and thyroid function tests. To our knowledge, this systematic molecular and clinical characterization of monosomy 1p36 is the largest and most comprehensive study of this deletion syndrome to date. Many cytogenetically visible, apparent terminal deletions are more complex than anticipated by cytogenetics, as revealed at the molecular level by our study. Our clinical findings allow for the more accurate recognition of the syndrome and for proper medical evaluation.

Chromosomal abnormalities, such as deletions and duplications, are characterized by specific and often complex phenotypes resulting from an imbalance in normal gene dosage. However, routine chromosome banding is not sensitive enough to detect subtle chromosome aberrations (<5-10 Mb). Array-based comparative genomic hybridization (array CGH) is a powerful new technology capable of identifying chromosomal imbalance at a high resolution by co-hybridizing differentially labeled test and control DNAs to a microarray of genomic clones. We used a previously assembled contig of large-insert clones that span 10.5 Mb of the most distal region of 1p36 to design a microarray. The array includes 97 clones from 1p36, 41 clones from the subtelomeric regions of all human chromosomes, and three clones from each of the X and Y chromosomes. We used this microarray to study 25 subjects with well-characterized deletions of 1p36. All array CGH results agree with the deletion sizes and locations of the breakpoints in these subjects as determined previously by FISH and microsatellite analyses. Terminal deletions, interstitial deletions, derivative chromosomes and complex rearrangements were also identified. We anticipate that array CGH will change the diagnostic approach to many congenital and acquired genetic diseases such as mental retardation, birth defects and cancer.

Two-by-two sequence alignment revealed that the levels of homology between 16s rRNA gene sequences of strains belonging to the two biovars of Ureaplusma urealyticum (class Mollicutes) ranged from 98.5 to 98.9%. Within the biovars, three serovars of the T960 biovar exhibited levels of homology of 299.7%, and the four serovars of the parvo biovar exhibited levels of homology of 299.7%. A dendrogram of the Mycoplusma pneumoniae-Ureaplusma clade of the Mollicutes reflected the distinctiveness of the biovars.Ureaplasmas of the genital tract of humans can act as commensal organisms or pathogens (14). Although these organisms are currently classified as members of a single species, differences in phenotypic and genotypic characteristics clearly divide Ureaplasma urealyticum strains into two biovars (9). The parvo biovar comprises serovars 1,3,6, and 14 and the T960 biovar comprises serovars 2, 4, 5, and 7 through 13. A recent comparison of the nucleotide sequences of the 16s rRNA genes of serovar 3 and 8 strains, representing the two biovars, revealed a level of homology of 98.8% (13). Exploitation of the single region of multiple-nucleotide variation in these strains allowed us to develop primers for PCRs. Using a PCR, we identified to biovar all laboratory-adapted and wildtype strains of U. urealyticum that we examined (6,13), and our results confirmed the genetic distinctiveness of each biovar. Our next goal was to determine the levels of homology of the highly conserved 16s rRNA gene within and between the two biovars.The sources and identities of the 14 serovar standard strains of U. urealyticum have been described previously (12). The seven strains examined in this study are identified below. The T960 biovar was represented by serovar 2, 5, and 8 strains. Despite serological cross-reactivity (4, ll), serovars 2 and 5 represent the extremes of the genome sizes (5, 7, 10) and restriction map arrangements (10) found in the serovars of the T960 biovar; the serovar 8 strain is the type strain. Because taxonomic changes primarily would affect the designation of the parvo biovar, all four of its serovar standard strains were examined.Primers which were used previously but now containing PstI or XhoI restriction sites were used to amplify target DNA by a PCR. The amplicons were restricted at the PstI and XhoI sites and were ligated into similarly restricted pBluescript I1 vector, which was then transformed into Escherichia coli LX1-blue. Transformants of the appropriate size were selected, and each insert was sequenced by the Sanger dideoxy sequencing reaction method. The sequences of the primers and the methods used have been described previously (3). Extraordinary care was taken to verify the sequence at those few sites where divergence occurred. For example, in one area of compression the nucleotide order was ascertained by the sensitivity of the site to restriction endonuclease activity, as confirmed by aga- rose gel electrophoresis. During the analyses we made changes to the previously published sequence of the gene...

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We examined the effect of 31 carbohydrates on the growth of Ureaplasma urealyticum and Mycoplasma hominis. Arbutin and its breakdown product, hydroquinone, inhibited growth of both species; the other substrates did not alter the extent of growth. Volatile and nonvolatile end products of carbohydrate metabolism were not detected by gas chromatography.