Evaluation of clinical checklists for fragile X syndrome screening in Brazilian intellectually disabled males: proposal for a new screening tool.

Patients with fragile X syndrome present a variable phenotype, which contributes to the underdiagnosing of this condition. The use of clinical checklists in individuals with intellectual disability can help in selecting patients to be given priority in the molecular investigation of the fragile X mutation in the FMR1 gene. Some features included in checklists are better predictors than others, but they can vary among different populations and with patient age.

Pure duplication 1q41-qter: further delineation of trisomy 1q syndromes.

Several authors have attempted to characterize the partial 1q trisomy syndrome, reporting clinical features such as mental retardation, macrocephaly, large fontanels, prominent forehead, broad flat nasal bridge, high-arched palate, micro/retrognathia, low-set ears, and cardiac defects. However, defining the partial trisomy 1q syndrome is difficult, because it is a rare chromosomal abnormality and in most instances the trisomy 1q is combined with partial monosomy of another autosomal segment. We report on the clinical and molecular cytogenetic study of a patient who presents pure partial 1q duplication.

Atypical 22q11.2 deletion in a patient with DGS/VCFS spectrum.

Deletions in region 22q11.2 usually occur between two low copy repeat regions (LCRs), which are preferred chromosome sites for rearrangements. Most of the deletions encompass the same approximately 3 or approximately 1.

Deletion 22q11.2: report of a complex meiotic mechanism of origin.

We report on the case of a patient with a typical de novo 3 Mb 22q11.2 deletion. Haplotype reconstruction of the family, using polymorphic markers flanking the deleted region, demonstrated a complex mechanism of origin of the deletion, involving one intrachromosomal and two interchromosomal events.

Breakpoint mapping in a case of mosaicism with partial monosomy 9p23 --> pter and partial trisomy 1q41 --> qter suggests neo-telomere formation in stabilizing the deleted chromosome.

We report on a clinical and molecular cytogenetic study of a patient who presents a complex chromosomal rearrangement with two different cell lines. Using high-resolution GTG banding and fluorescence in situ hybridization (FISH) with several probes, including bacterial artificial chromosomes (BACs), the karyotype was defined as 46,XX,del(9)(p23)[54]/46,XX,der(9)t(1;9)(q41;p23)[46], indicating the presence of monosomy 9p23 in all cells and trisomy 1q41 in approximately 50% of the cells. The patient studied presents most of the manifestations of the 9p deletion and 1q duplication syndromes.