Holt-Oram syndrome
A genetic syndrome characterized by the combination of heart disease and malformations of the upper limb. The heart defect is usually an atrial septal defect (ASD) and, less often, a ventricular septal defect (VSD), although other cardiovascular malformations have been reported. The upper limb malformations most often affect the forearm and thumb. The thumb may be absent or it may be a nonopposable fingerlike digit. All gradations in defects in the upper limb and shoulder girdle have been reported.
The Holt-Oram syndrome (HOS) is inherited in an autosomal dominant manner and is due to mutations in the TBX5 (T-box 5) gene located in chromosome region 12q24.1. The GATA4 (GATA-binding protein 4) gene is known to interact with TBX5.
The syndrome was first clearly delineated in 1960 by M. Holt and Samuel Oram as “Familial heart disease with skeletal malformations.” Called also the heart-hand syndrome, cardiac-limb syndrome, and atriodigital dysplasia.
Read Also:
- Holter monitor
A type of portable heart monitor that is a small electrocardiogram (EKG) device worn in a pouch around the neck or waist. A Holter monitor keeps a record of the heart rhythm, typically over a 24-hour period, and the patient keeps a diary of activities and symptoms. The EKG recording is then correlated with the […]
- Homeobox gene
A gene containing a short DNA sequence of about 180 base pairs referred to as a homeobox. Homeobox genes encode proteins that bind and regulate the expression of DNA in multicellular organisms. Homeoboxes are present in the genomes of many organisms from fruit flies to humans, and they appear to determine when particular groups of […]
- Homeopath
A person who practices homeopathy.
- Homeopathy
Founded in the 19th century, a practice that is based on the concept that disease can be treated with minute doses of drugs thought capable of producing in healthy people the same symptoms as those of the disease being treated. This principle is similar to the concept behind exposure therapy for allergies, but the amounts […]
- Homeostasis
A property of cells, tissues, and organisms that allows the maintenance and regulation of the stability and constancy needed to function properly. Homeostasis is a healthy state that is maintained by the constant adjustment of biochemical and physiological pathways. An example of homeostasis is the maintenance of a constant blood pressure in the human body […]