Inheritance of a lethal immunodeficiency disease of Arabian foals.

This research article focuses on a lethal immunodeficiency disease found in Arabian foals, identifying it as a genetic disorder transmitted through a simple recessive autosomal gene.

Key Aspects of the Study

• The study primarily concentrates on a fatal syndrome found in Arabian foals, affecting 17 foals from a single farm. This syndrome is characterized by a gradual deterioration of health, eventually leading to death.
• The foals began showing symptoms of the syndrome around 25 days old, with the disease leading to death approximately 49 days after birth. The youngest foals started showing signs of the syndrome at 14 days old and the oldest at 46 days old.
• The duration of the disease varied among the foals, ranging from 13 to 42 days.

Key Symptoms and Evidence

• A common symptom among the affected foals is pneumonia. Some cases also showed instances of dermatitis (dermatophilosis) and other multiple infections.
• Upon histopathological examination, four foals displayed evidence of adenoviral pneumonia. An adenovirus, which can lead to respiratory diseases, was isolated from one foal.
• Two foals showed histopathological signs pointing towards an immunodeficiency disease.

Lethal Immunodeficiency Disease: An Inherited Affliction

• Despite the differing symptoms and evidence, the researchers argued that all 17 foals were affected by the same underlying immunodeficiency disease. This syndrome caused multiple infections and led to a progressive decline in health until death.
• Based on their examination and evidence, the researchers proposed that this immunodeficiency disease is inherited. More specifically, it is passed down via a simple, recessive, autosomal gene.
• In other words, the disease only manifests when the offspring inherits the recessive gene from both parents. This type of gene is found on any of the 22 pairs of non-sex chromosomes (autosomal), meaning the disease can affect both male and female foals equally.