Scientists have identified the genetic cause of a birth defect known as Hamamy syndrome. The work lends new insights into common ailments such as heart disease, osteoporosis, blood disorders, and possibly sterility.

Hamamy syndrome is a rare genetic disorder, which is marked by abnormal facial features and defects in the heart, bone, blood, and reproductive cells.

Scientists from A*STAR’s Institute of Medical Biology (IMB; Singapore), in collaboration with doctors and scientists in Jordan, Turkey, Switzerland, and the United States made the discovery and published their findings in the May 13, 2012, journal Nature Genetics. The international team pinpointed the genetic mistake to be a mutation in a single gene called IRX5. This is the first time that a mutation in IRX5 (and the family of IRX genes) has been discovered in man.

IRX5 is part of a family of transcription factors that is highly conserved in all animals, and is found in humans, mice, fish, frogs, flies, and worms. Using a frog model, the scientists demonstrated that IRX5 organizes cell movements in the developing fetus that underlie head and gonad formation.

The IMB investigators believe that their discovery could help the development of therapeutic solutions to common diseases such as osteoporosis, heart disease, and anemia.

Carine Bonnard, a final-year PhD student at IMB and the first author of the paper, said, “Because Hamamy syndrome causes a wide range of symptoms, not just in newborn babies but also in the adult, this implies that IRX5 is critical for development in the womb as well as for the function of many organs in our adult body. For example, patients with this disease cannot evacuate tears from their eyes, and they will also go on to experience repetitive bone fractures or progressive myopia as they age. This discovery of the causative gene is a significant finding that will catalyze research efforts into the role of the Irx gene family and greatly increase our understanding of human health, such as bone homeostasis, or gamete formation, for instance.”

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A*STAR’s Institute of Medical Biology