The Genetic Components of Rare Diseases

Techniques for determining which genes or genetic variants are truly detrimental

Last fall, the conclusion of the 1000 Genomes Project revealed 88 million variants in the human genome. What most of them mean for human health is unclear. Of the known associations between a genetic variant and disease, many are still tenuous at best. How can scientists determine which genes or genetic variants are truly detrimental?

Patients with rare diseases are often caught in the crosshairs of this uncertainty. By the time they have their genome, or portions of it, sequenced, they’ve endured countless physician visits and tests. Sequencing provides some hope for an answer, but the process of uncovering causal variants on which to build a treatment plan is still one of painstaking detective work with many false leads. Even variants that are known to be harmful show no effects in some individuals who harbor them, says Adrian Liston, a translational immunologist at the University of Leuven in Belgium who works on disease gene discovery.

Read more: The Genetic Components of Rare Diseases

CROSS COMPARE: Each model organism has its own vocabulary that researchers use to describe
an array of characteristics. The Monarch Initiative has mapped phenotype descriptions used in model
systems to human clinical features. The Initiative’s Exomiser software employs this mapping strategy
to help users better understand human genetic disorders by widening the pool of gene-function
associations. ROBINSON ET AL., GENOME RES, 24:340–48, 2014.

Source: the-scientist

Diagnosis of Pneumocystis jirovecii pneumonia

Diagnosis of Pneumocystis jirovecii pneumonia (PCP) is conventionally based on direct staining and visualization. Challenges in obtaining alveolar samples have stimulated interest in techniques for detection of Pneumocystis DNA in non-invasive samples, which can give good sensitivity and specificity. Robust diagnosis is key to ensuring appropriate therapy.

Introduction

Pneumocystis jirovecii (previously Pneumocystis carinii) is a pathogen capable of causing life threatening Pneumocystis pneumonia (PCP) in the immunocompromised with case fatality rates among those hospitalized of around 10%. PCP typically occurs in individuals with hematological malignancies on chemotherapy or with other causes of acquired cellular immunodeficiency or, most frequently, in human immunodeficiency virus (HIV)-positive individuals with CD4 T-cell counts <200 cells/µL or <14% of total white cell count. First-line treatment is co-trimoxazole, a combination of the antibiotics sulfamethoxazole and trimethoprim, at high dose for 3 weeks, which has the clinically significant potential side effects of bone marrow suppression, rash and bronchial hypersensitivity.

Read more: Diagnosis of Pneumocystis jirovecii pneumonia

Source: ClinicalLaboratoryInternational