An atrioventricular septal defect results in a is a large hole between the upper filling chambers (atria) and the lower pumping chambers (ventricles) of the heart. There is also only one valve between the atria and ventricles instead of two.
The aortic valve is a one-way valve between the left pumping chamber (ventricle) of the heart and the major blood vessel taking blood to the body (aorta). Aortic stenosis (AS) describes a condition where the aortic valve is smaller or tighter than it should be.
Aortic regurgitation occurs when the aortic valve (linking the left ventricle to the aorta) does not close properly when the heart contracts. This means blood leaks back into the left ventricle, which then has to work harder to pump the extra blood away from the heart to the rest of the body. This can lead to the enlargement and thickening of the ventricle wall.
Langerhans' cell histiocytosis (LCH) is a very rare condition with a high survival rate. Histiocyte cells normally help protect the skin, but sometimes the body has too many of them and they move around the body, causing damage.
Congenital hypothyroidism is a disorder affecting the thyroid gland, which is in the neck. The thyroid gland produces a hormone (chemical substance) called thyroxine, which is needed for normal growth and development.