King Saud University’s Dr. Muslim Al-Saadi and Dr. Khalid K. Alharbi have collaborated with a British research team, led by Bristol University’s Dr. Ian N. M. Day, in the discovery of a gene behind Primary Ciliary Dyskinesia (PCD), a rare genetic pulmonary disorder that affects children.
Known also as Immotile Ciliary Syndrome or Kartagener Syndrome (KS), PCD causes a defect in the action of the cilia lining in the respiratory tract (lower and upper, sinuses, Eustachian tube, and middle ear), the fallopian tub and the flagella of male sperm.
The study and its findings were explained in a research article, published in the March 2, 2012 edition of the scientific journal Annals of Human Genetics, and entitled From a Single Whole Exome Read to Notions of Clinical Screening: Primary Ciliary Dyskinesia and RSPH9 p.Lys268del in the Arabian Peninsula.
Dr. Al-Saadi is an associate professor in KSU's Department of Pediatrics and the College of Medicine's Vice Dean for Academic Affairs, while Dr. Alharbi is an associate professor of genetic diseases in the College of Applied Medical Sciences. Dr. Day, a visiting professor at KSU, is Deputy Director of the MRC Centre (Causal Analysis in Translational Epidemiology) at the University of Bristol.
Data compiled by the team shows that the gene causing this disease is particularly prevalent in the Gulf region and has spread geographically across several generations. The researchers used state of the art technologies for their research, enabling them to draw genetic maps to pinpoint the gene.
“Exploring the genetic map of one person to find the guilty gene is very complicated but we did it and it opens the way to draw a direct genetic sequence,” one of the researchers said. “This was like finding the proverbial needle in the haystack. But we did it and a PCD test will soon become a reality.”
Respiratory epithelial motile cilia resemble microscopic hairs, although they structurally and biologically are unrelated to hair and are complex organelles that beat synchronously in the respiratory tract, moving mucus toward the throat. Normally, cilia beats 7 to 22 times per second and any impairment can result in poor mucociliary clearance with upper and lower respiratory infection. Cilia also are involved in other biological processes.
Researchers also discovered that this condition worsens with the prevalence of co-sanguinary marriages especially among first cousins. Diagnosis is frequently missed early in victims and progressive damage to the respiratory system is common. No specific data is available as to how many suffer from this condition, but estimates range anywhere from 1 in 15,000 to 1 in 32,000 individuals.
Some symptoms of PCD include hearing loss and a poor sense of touch or taste. The hearts of some victims are situated on the right side of their chest. Experts emphasize that early diagnosis greatly reduces damage to the nasal cavities and chronic lung diseases such as pulmonary vesiculation.
It is not uncommon for PCD to be mistaken for cystic fibrosis and genetic screening remains the best technique to avert it or treat it and the presence of the RSPH9 is one of the most significant signs of PCD. Testing can, in stages, be conducted on an entire family of PCD patients to identify new cases of PCD and as an indicator of upcoming cases. The genetic test allows a couple to opt for artificial insemination instead of natural pregnancy if either of both parents carries this gene.
What researchers need now is to conduct a detailed mapping of the geographic spread of the PCD gene in various tribal areas in the Kingdom and the Gulf. Genetic scanning also could target groups of patients with similar diseases such as bronchitis and asthma, diagnose children suffering from individual or collective ENT problems, identify young adults suffering from Infertility because of PCD and overall assess the overall spread of the syndrome.
Other genes which cause PCD exist, but the research of PCD is still in its infancy. Recent research results, however, will hopefully lead to a new era in the diagnosis and treatment of chronic respiratory diseases among children.
The research team closed by expressing thanks and gratitude to KSU Rector Abdullah Al-Othman and Dr. Ali Al-Ghamdi, Vice Rector for Graduate Studies and Scientific Research, for their unyielding support for their research.