The frequency is unknown but it appears to be a common cause of sudden and unexplained death in children and young adults. It is certainly much more common than previously thought. It may be as frequent as 1 in 5000 to 7000. This means, one of 5000 to 7000 newborns have the disease. The Jervell, Lange-Nielsen form is rare, but the Romano-Ward variant is being recognized with increasing frequency. In the USA, the presence of long QT syndrome is estimated to affect about 50.

The long QT syndrome (LQTS) is causing an abnormality of the heart's electrical system. The mechanical function of the heart is entirely normal. The electrical problem is due to defects in heart muscle cell structures called ion channels. These electrical defects predispose affected persons to a very fast heart rhythm (arrhythmia) called "Torsade de Pointes" (TdP) which leads to sudden loss of consciousness (syncope) and may cause sudden cardiac death.

The diagnosis is commonly suspected or made from the electrocardiogram (ECG). All children and young adults should have an ECG as part of their evaluation for an unexplained loss of consciousness episode. On the other hand, there is the possibility to check blood samples for known gene mutations that cause LQTS.

The name of the long QT syndrome refers to the QT-interval measured on the electrocardiogram (ECG or EKG for the German term "Elektrokardiogramm"). Your specialist may refer to long QT syndrome as Romano-Ward syndrome or Jervell, Lange-Nielsen syndrome (see point 3).

INHERITED: Inherited long QT syndrome was first clearly described in 1957. There are two variants, the autosomal dominant Romano-Ward (named by the doctors who first described the disease, O. Connor Ward and C. Romano) type and the autosomal recessive Jervell, Lange-Nielsen (Doctors A. Jervell, F. Lange-Nielsen) type. Inherited long QT syndrome is caused by mutations of at least 9 genes, and possibly more. Five different genes have so far been found.

It is generally estimated that approximately 10% to 12% of all patients with long QT syndrome show a normal QT-interval on their ECG. However, this does not mean that these patients are not affected by long QT syndrome. In such cases, a more profound evaluation is needed.

It has been noticed that several cardiac arrests occur during summer time. But it is not sure if it this may be an excess in statistical terms. It is however hard to define if these cardiac arrests are related to a specific "risk" due to heat or sweating or if it is mainly a reflection of increased physical activity, excitement and playing during the summer.

The 9-month interval during pregnancy and the delivery itself are not associated with an increased occurrence of heart events in any of the LQTS women. However, it appears that the physical and emotional stress during the 9-month period after pregnancy (the postpartum period) may be a factor in triggering heart rhythm disorders in some vulnerable women with LQTS.

There are two ways to make a diagnosis for QT syndrome. The first is to check if the QT-interval on the ECG of a suspected patient is prolonged. Because the heart stopps beating when death occurs, this possbility is out of question - except an ECG of the dead person already exists, of course. The only possibility would be to check body fluids of the dead person - in this case blood - for the known gene mutations that cause QT syndrome.

Studies show there are significant gender differences in genotyped LQTS patients relative to age of first episode, syncope, cardiac arrest and sudden death. Males seem to have a higher risk of cardiac events (meaning syncope or blackout spells, cardiac arrest and sudden death) during childhood (with an average earlier age of onset in males at 8 years old vs.14 years in females), through puberty. Studies reveal females have an increased risk relative to males during adulthood.

Only 3 to 5% of cases are inherited; the rest arise as an accident of chromosome arrangement during meiosis. For details, see my essay on the origin of trisomy 21 or Dr. Paul Benke's essay on the types of DS, and the risk and recurrence risk of DS. No. Down syndrome occurs at conception, so nothing in the pregnancy can cause Down syndrome to occur. As for prior to conception, the research all shows that drug or alcohol use does not increase the risk of having a child with DS.

Most of the studies in the medical literature confirm that no major differences exist between brand and generic drugs. However it is fair to recognize that occasional reports have raised concern that certain generic brands may be less effective than brand name products (see: Cervera Barba EJ. [Increase of arterial pressure caused by generic atenolol] Aten Primaria. 2001 Feb 15;27(2):146-8).

Retinal degenerations affect men and women of all ages, races, cultures, and ethnic backgrounds. The broad range of retinal degenerative diseases affects at least six million Americans. Approximately 100,000 people in the United States are affected by retinitis pigmentosa or Usher syndrome, which is a variation of RP that also impairs hearing.

Genetic studies suggest that individuals with significant symptoms have inherited multiple genes from both parents, i.e. it is polygenic. The associated behaviors listed above are common in the relatives of TS individuals. See the Research Articles for many of the genetic studies carried out at the City of Hope Tourette Syndrome/ADHD clinic. Is Tourette Syndrome a Progressive or Fatal Disorder? No. TS not a progressive disorder.

In two large studies it was found that about 1 in 6 adults reported some symptoms of an overactive bladder. Symptoms vary in their severity. About 1 in 3 people with an overactive bladder have episodes of urge incontinence.

Yes.  Current medical literature seems to have reached the consensus that a child, in a situation where one parent has Crouzon Syndrome, has roughly a fifty percent chance of being born with the condition. It is interesting to note that Dr. Crouzon, in his initial 1912 report, labeled the disease "hereditary craniofacial dysostosis". Yes, and it frequently does.  Statistics seem to suggest that Crouzon Syndrome occurs spontaneously in twenty-five to fifty percent of cases.

TS was once thought to be a rare disease. However studies of ours in a Los Angeles school district indicate 1 in 100 school boys had TS. It is less common in girls. Subsequent studies in New York and England suggest an ever higher incidence. This makes it one of the commonest genetic disease affecting children. Because of the wide range of associated problems, TS is an important factor in many children with school and behavioral problems.

is much more common than previously realized and many adults are undiagnosed. Studies suggest that AS is considerably more common than "classic" Autism. Whereas Autism has traditionally been thought to occur in about 4 out of every 10,000 children, estimates of Asperger Syndrome have ranged as high as 20-25 per 10,000. A study carried out in Sweden , concluded that nearly 0.7% of the children studied had symptoms suggestive of AS to some degree.

Women are more likely than men to be affected by Antiphospholipid Antibody Syndrome. Some estimates say that 75% to 90% of those affected are women. For example, it has been estimated by some doctors that one third of all of young strokes (defined as under the age of 50) are due to Antiphospholipid Antibody Syndrome. In obstetrics it is estimated by some doctors that up to 25% of all women with 2 or more spontaneous miscarriages have Antiphospholipid Antibody Syndrome.

Down's Syndrome is in fact the most common of all learning disabilities approaching around 30% of all severe learning disability and featuring in 1 in 1000 births.

Frankly, Irritable Bowel Syndrome is extremely common. Anyone can be affected with it, but only a small percentage of people with IBS are treating the disorder.

The duration of the QT-interval is a measure of the time required for depolarization and repolarization to occur. In long QT syndrome, the duration of repolarization is longer than normal. Thus, the QT-interval is prolonged. An interval above 440 milliseconds (msec) is considered prolonged. QT-prolongation in is due to overload of myocardial cells with positively charged ions during ventricular repolarization.

to 470 milliseconds is considered borderline. The average QTc for someone who has long-QT syndrome is 490 milliseconds. A QTc at or above 480 milliseconds in females or 470 milliseconds in males, is probably a sign for long-QT syndrome, in the absence of drugs, electrolyte disturbance, or other conditions that might independently lengthen the QT-interval.

Around 50% of children and adults with reading problems have Irlen Syndrome. For some, Irlen Syndrome will be just part of the puzzle as they will have other reading/learning problems that need to be addressed, too. Irlen Filters will make the print clear and easy to see the page comfortably.

Studies show that about 25% of women have fibromas. They cause no problems unless they are large. There is no evidence that they affect fertility.

Reye syndrome is rare. Since 1994, two or fewer cases per year are reported in the U.S. There has been a dramatic decline of cases since the 1980s, when health experts began educating parents about the use of aspirin and aspirin-containing products for the treatment of chickenpox and other flu-like illnesses. Reye syndrome cases occur throughout the year, but are more frequent when viral diseases are epidemic, such as the winter months, or following an outbreak of chickenpox or influenza.

Genetics may play a role in PMDD. Studies have shown that identical twins are more likely to share the disorder (93%) than non-identical (fraternal) twins (44%), and daughters of mothers with PMDD are more likely to have it themselves. However, no specific genes have been identified to account for PMDD. It is best to simply say that genetics may put a woman at greater risk for developing the disorder.

There is a genetic factor in the development of allergic disease. If one parent has allergic disease, the estimated risk of a child to develop allergies is 48%; the child's estimated risk grows to 70% if both parents have a history of allergies.