The further development of enzyme assays demonstrated that levels of hexosaminidases A and B could be measured in patients and carriers, allowing the reliable detection of heterozygotes. During the early 1970s, researchers developed protocols for newborn testing, carrier screening, and pre-natal diagnosis. By the end of 1979, researchers had identified three variant forms of GM2 gangliosidosis, including Sandhoff disease and the AB variant of GM2-gangliosidosis, accounting for false negatives in carrier testing. Society and culture
Since carrier testing for Tay–Sachs began in 1971, millions of Ashkenazi Jews have been screened as carriers. Jewish communities embraced the cause of genetic screening from the 1970s on. The success with Tay–Sachs disease has led Israel to become the first country that offers free genetic screening and counseling for all couples and opened discussions about the proper scope of genetic testing for other disorders in Israel.Because Tay–Sachs disease was one of the first autosomal recessive genetic disorders for which there was an enzyme assay test (prior to polymerase chain reaction testing methods), it was intensely studied as a model for all such diseases, and researchers sought evidence of a selective process. A continuing controversy is whether heterozygotes (carriers) have or had a selective advantage. The presence of four different lysosomal storage disorders in the Ashkenazi Jewish population suggests a past selective advantage for heterozygous carriers of these conditions. "This controversy among researchers has reflected three debates among geneticists at large:
Dominance versus overdominance.
This results in bradycardia, vasodilation, flushing, pupillary constriction and nasal stuffiness above the spinal lesion, while there is piloerection, pale and cool skin below the lesion due to the prevailing sympathetic outflow.Initial treatment involves sitting the patient upright, removing any constrictive clothing (including abdominal binders and support stockings), rechecking blood pressure frequently, and then checking for and removing the inciting issue, which may require urinary catheterization or bowel disimpaction. If systolic blood pressure remains elevated (over 150 mm Hg) after initial steps, fast-acting short-duration antihypertensives are considered, while other inciting causes must be investigated for the symptoms to resolve.Prevention of AD involves educating the patient, family and caregivers of the precipitating cause, if known, and how to avoid it, as well as other triggers. Since bladder and bowel are common causes, prevention involves routine bladder and bowel programs and urological follow-up for cystoscopy/urodynamic studies. Signs and symptoms
This condition is distinct and usually episodic, with the people potentially experiencing remarkably high blood pressure, intense headaches, profuse sweating, facial erythema, goosebumps, nasal stuffiness, a "feeling of doom" or apprehension, and blurred vision. An elevation of 20 mm Hg over baseline systolic blood pressure, with a potential source below the neurological level of injury, meets the current definition of dysreflexia. Complications
Autonomic dysreflexia can become chronic and recurrent, often in response to longstanding medical problems like soft tissue pressure injuries or hemorrhoids. Long term therapy may include alpha blockers or calcium channel blockers.Complications of severe acute hypertension can include seizures, pulmonary edema, myocardial infarction, or cerebral hemorrhage.