These orthostatic symptoms include palpitations, light-headedness, chest discomfort, shortness of breath, nausea, weakness or "heaviness" in the lower legs, blurred vision, and cognitive difficulties. Differential diagnoses
A variety of autonomic tests are employed to exclude autonomic disorders that could underlie symptoms, while endocrine testing is used to exclude hyperthyroidism and rarer endocrine conditions. Electrocardiography is normally performed on all patients to exclude other possible causes of tachycardia. In cases where a particular associated condition or complicating factor are suspected, other non-autonomic tests may be used: echocardiography to exclude mitral valve prolapse, and thermal threshold tests for small-fiber neuropathy.Testing the cardiovascular response to prolonged head-up tilting, exercise, eating, and heat stress may help determine the best strategy for managing symptoms. POTS has also been divided into several types (see § Causes), which may benefit from distinct treatments. People with neuropathic POTS show a loss of sweating in the feet during sweat tests, as well as impaired norepinephrine release in the leg, but not arm. This is believed to reflect peripheral sympathetic denervation in the lower limbs. People with hyperadrenergic POTS show a marked increase of blood pressure and norepinephrine levels when standing, and are more likely to have from prominent palpitations, anxiety, and tachycardia.People with POTS can be misdiagnosed with inappropriate sinus tachycardia (IST) as they present similarly. One distinguishing feature is those with POTS rarely exhibit >100 bpm while in a supine position, while patients with IST often have a resting heart rate >100 bpm.
Laryngo-onycho-cutaneous syndrome (also known as Shabbir syndrome) is a rare epithelial disorder inherited in an autosomal recessive fashion. It is characterized by abnormalities in the larynx, nails ("onycho-"), and skin ("cutaneous"). The disorder is only found in Punjabi Muslims and only a few cases have been reported.It was characterized by Pakistani dermatologist Syed Ghulam Shabbir (1923–2002) in 1986.It may be associated with LAMA3. See also
Watson syndrome
List of cutaneous conditions

References
External links
Laryngo-onycho-cutaneous syndrome on MedlinePlus