Ehlers-Danlos Syndrome (EDS): Given the combination of joint hypermobility, kyphosis, and multiple systemic symptoms such as supraventricular tachycardia (SVT), gastrointestinal issues, and asthma, EDS is a strong consideration. EDS is a group of disorders that affect connective tissues supporting the skin, bones, blood vessels, and many other organs and tissues, which aligns with the patient's diverse symptoms.

Marfan Syndrome: This genetic disorder affects the body's connective tissue and can lead to features such as tall stature, joint hypermobility, and an increased risk of cardiovascular issues, including arrhythmias like SVT. While the presence of kyphosis and gastrointestinal issues could fit, the absence of other key features like aortic root dilatation or significant ocular findings might make this less likely.
Postural Orthostatic Tachycardia Syndrome (POTS): Often associated with EDS, POTS involves a rapid increase in heart rate upon standing, which could explain the SVT. Gastrointestinal issues and asthma might also be seen in the context of autonomic dysfunction associated with POTS.
Hypermobility Spectrum Disorder: For patients who do not meet the full criteria for EDS but have significant joint hypermobility and related symptoms, this diagnosis might be considered. However, the presence of systemic symptoms like SVT and gastrointestinal issues might lean more towards EDS.

Mitral Valve Prolapse: A condition where the two valve flaps of the mitral valve do not close smoothly or evenly, which can lead to arrhythmias and might be associated with systemic symptoms. It's crucial to rule out due to the potential for severe cardiac complications.
Autonomic Dysfunction: Conditions affecting the autonomic nervous system can lead to a wide range of symptoms including orthostatic intolerance, gastrointestinal dysmotility, and respiratory issues, which could mimic or contribute to the patient's presentation.

Stickler Syndrome: A genetic disorder that affects connective tissue and is characterized by distinctive facial features, eye abnormalities, hearing loss, and joint problems. While it shares some features with EDS, its distinctiveness and rarity make it less likely.
Loeys-Dietz Syndrome: A disorder that affects the connective tissue in the body and is characterized by features such as tall stature, joint hypermobility, and an increased risk of aortic aneurysms. The presence of systemic symptoms could fit, but the specific constellation of features and the rarity of the condition make it a less likely diagnosis without more specific indicators like significant aortic root dilatation or a family history.