Kabuki syndrome is not caused by an 8p duplication: a cytogenetic study in 20 patients.

Kabuki syndrome is characterized by a typical facial gestalt in combination with hypotonia and joint laxity, developmental delay, persistent fetal fingertip pads, and structural abnormalities mainly of the palate and the heart. Cytogenetic conditions may present with features of the syndrome. Recently, Milunsky and Huang [2003], reported an 8p duplication at chromosome 8p22-8p23.

Characterization of a chromosome 8-derived minute marker chromosome using microdissection and FISH in a boy with growth retardation.

In a 9-year-old boy referred because of growth retardation, chromosome analysis showed the presence of a minute marker chromosome in 75% of the metaphases examined. The application of microdissection in combination with fluorescence in situ hybridization demonstrated that the marker was derived from the centromere region of chromosome 8, the karyotype being: mos 47,XY,+mar.ish der(8)(D8Z1+)[75]/46,XY[25].

ICF syndrome: a new case and review of the literature.

Patients with ICF syndrome can be recognized by the presence of a variable immunodeficiency, instability of the pericentromeric heterochromatin of, in particular, chromosomes 1, 9, and 16 in cultured peripheral lymphocytes, and a number of facial anomalies. Recently, aberrations at the molecular level have been described, consisting of alterations in the methylation pattern of classical satellite DNA, in a number of patients. ICF syndrome is considered to be inherited in an autosomal recessive manner and may be rare, as only 14 patients have been described thus far.

Distribution of meiotic recombination along nondisjunction chromosomes 21 in Down syndrome determined using cytogenetics and RFLP haplotyping.

Ten families (Down syndrome children and their parents) showing evidence of meiotic recombination between intraparental chromosomes transmitted after nondisjunction were studied. Cytogenetic polymorphisms and a cassette of RFLP markers distributed along chromosome 21 were used to analyze these families to localize the regions of meiotic recombination. Results indicated that only one crossover occurred per meiotic division and that nine of ten nondisjunctions appeared to be of maternal origin.

On the origin of recurrent trisomy 21: determination using chromosomal and DNA polymorphisms.

A family is described in which two cases of trisomy 21 occurred in, respectively, a newborn infant and a prenatally diagnosed fetus. Using fluorescent chromosomal polymorphisms, it was established that in both cases the extra chromosome resulted from a first meiotic division error in the mother and that the father contributed the same centromeric region to both children. RFLP-associated probes were used to examine the genetic content of the chromosomes.