De novo balanced chromosome rearrangements in prenatal diagnosis.

Objective: We surveyed the datasheets of 29 laboratories concerning prenatal diagnosis of de novo apparently balanced chromosome rearrangements to assess the involvement of specific chromosomes, the breakpoints distribution and the impact on the pregnancy outcome.

Method: By means of a questionnaire, data on 269.371 analyses performed from 1983 to 2006 on amniotic fluid, chorionic villus and fetal blood samples were collected.

Cytogenetic and molecular evaluation of 241 small supernumerary marker chromosomes: cooperative study of 19 Italian laboratories.

Purpose: We evaluated the experiences of 19 Italian laboratories concerning 241 small supernumerary marker chromosomes (sSMCs) with the aim of answering questions arising from their origin from any chromosome, their variable size and genetic content, and their impact on the carrier's phenotype.

Methods: Conventional protocols were used to set up the cultures and chromosome preparations. Both commercial and homemade probes were used for the fluorescent in situ hybridization analyses.

Pure 6p22-pter trisomic patient: refined FISH characterization and genotype-phenotype correlation.

First described in 1971, partial trisomy 6p is uncommon and generally secondary to a familial reciprocal translocation. The proximal breakpoint of the reported cases varies from p11 to p25. We here report on a patient with moderate mental retardation, craniofacial and pigmentary anomalies, proteinuria, and hyperglycemia who was found to have a mosaic karyotype 46,X,add(Y)(q12)/45,X.

Inv dup (8) (p21.1----22.1): further case report and a new hypothesis on the origin of the chromosome abnormality.

We report a male infant with a de novo inverted duplication of bands 8p 21.1----22.1.

Terminal deletion of the long arm of chromosome 10: case report and review of the literature.

We report on a newborn girl with a terminal deletion of the long arm of chromosome 10: del (10)(pter----q26). The phenotypic manifestations are compatible with those of the previously reported cases. In addition, the association with abnormalities of the urinary tract is reported for the first time.

Terminal deletion of the short arm of chromosome 5.

Three cases of deletion of the short arm of chromosome 5 are described: one family cluster, in which the mother and three sons are affected, and two sporadics without the typical "cri du chat" phenotype (the family and Case 2 were previously reported in 1982). Mental retardation varied between affected members of the same family. Band p15.

A new chromosome instability disorder.

Chromosome analysis in a 31-year-old woman referred for primary amenorrhea, revealed a very high incidence of chromosome aberrations. She had microcephaly and immunodeficiency. Her healthy parents were consanguineous (1/32) and a younger sister, also with primary amenorrhea, died when 20 years old with a malignant lymphoma.

Ring chromosome 21 in phenotypically apparently normal persons: report of two families from Switzerland and Italy.

If a ring 21, originating from breaks close to the telomere of 21q and anywhere in 21p, replaces a normal 21, it may be associated with an apparently normal phenotype. An apparently normal mother and son were ascertained by a prenatal chromosome study. A second mother, with a ring 21 but without gross anomalies, is short of stature, has epilepsy and has a low normal intelligence.

Deficiency, transposition, and duplication of one 15q region may be alternatively associated with Prader-Willi (or a similar) syndrome. Analysis of seven cases after varying ascertainment.

Seven patients are described who have some or all of the symptoms of Prader-Willi syndrome. They were ascertained by varying criteria starting either from the clinical picture or from the identification of a chromosome abnormality involving the proximal portion of the long arm of chromosome 15. The chromosome abnormalities consisted of two balanced translocations (15;18 and 8;15), three unbalanced ones (15;18, 15;19, and 9;15), and one interstitial deletion of bands 15q11 and q12.

The 11q;22q translocation: a collaborative study of 20 new cases and analysis of 110 families.

Following a previous collaborative study (Fraccaro et al. 1980), 20 new cases of 11q;22q translocation are described. Twelve families were ascertained through an unbalanced carrier of the translocation and eight cases were ascertained as balanced carriers.