Autosomal ring chromosomes in human genetic disorders.

Ring chromosomes arise following breakage and rejoining in both chromosome arms. They are heterogeneous with variable size and genetic content and can originate from any chromosome. Phenotypes associated with ring chromosomes are highly variable as apart from any deletion caused by ring formation, imbalances from ring instability can also occur.

Uniparental disomy in Robertsonian translocations: strategies for uniparental disomy testing.

Robertsonian translocations (ROBs) are whole arm rearrangements involving the acrocentric chromosomes 13-15 and 21-22 and carriers are at increased risk for aneuploidy and thus uniparental disomy (UPD). Chromosomes 14 and 15 are imprinted with expression of genes dependent on the parental origin of the chromosome. Correction of a trisomic or monosomic conceptus for chromosomes 14 or 15 would lead to one of the established UPD 14mat/pat or UPD 15 (Prader-Willi/Angelman) syndromes (PWS/AS).

A comparison of molecular and cytogenetic techniques for the diagnosis of pregnancy loss.

Purpose: To evaluate the sensitivity, specificity, advantages, and limitations of multiplex ligation-dependent probe amplification compared with conventional karyotype analysis in the investigation of contributing factors to recurrent pregnancy loss.

Method: A cohort of 284 patients underwent side-by-side analysis of products of conception by both conventional karyotyping and multiplex ligation-dependent probe amplification with direct comparison of results.

Results: Multiplex ligation-dependent probe amplification was shown to enable a diagnosis for an additional 47 (16.