Hypertrophic cardiomyopathy (HCM) is defined by the presence of increased ventricular wall thickness or mass in the absence of loading conditions (hypertension, valve disease) sufficient to cause the observed abnormality.

A hole between the two bottom chambers (ventricles) of the heart. The defect is centered around the most superior aspect of the ventricular septum.

Accumulation of fluid within the pericardium.

A rare congenital vascular anomaly that results when the left superior cardinal vein caudal to the innominate vein fails to regress.

A slower than normal heart rate (in adults, slower than 60 beats per minute).

An abnormal restriction of fetal growth with fetal weight below the tenth percentile for gestational age.

Smaller than normal size according to sex and gestational age related norms, defined as a weight below the 10th percentile for the gestational age.

Hard, pebble-like deposits that form within the gallbladder.

Impaired feeding performance of an infant as manifested by difficulties such as weak and ineffective sucking, brief bursts of sucking, and falling asleep during sucking. There may be difficulties with chewing or maintaining attention.

A type of Developmental delay characterized by a delay in acquiring motor skills.

A reduction in the number of circulating thrombocytes.

An abnormality of the process of blood coagulation. That is, altered ability or inability of the blood to clot.

Hypotonia is an abnormally low muscle tone (the amount of tension or resistance to movement in a muscle). Even when relaxed, muscles have a continuous and passive partial contraction which provides some resistance to passive stretching. Hypotonia thus manifests as diminished resistance to passive stretching. Hypotonia is not the same as muscle weakness, although the two conditions can co-exist.

Reduced strength of muscles.

Hyperventilation refers to an increased pulmonary ventilation rate that is faster than necessary for the exchange of gases. Hyperventilation can result from increased frequency of breathing, an increased tidal volume, or both, and leads to an excess intake of oxygen and the blowing off of carbon dioxide.

An abnormal buildup of lactic acid in the body, leading to acidification of the blood and other bodily fluids.

Reduced body temperature due to failed thermoregulation.

An elevation of the level of the enzyme creatine kinase (also known as creatine phosphokinase (CK; EC 2.7.3.2) in the blood. CK levels can be elevated in a number of clinical disorders such as myocardial infarction, rhabdomyolysis, and muscular dystrophy.

A form of lactic acidemia that occurs in relation to stress or infection.

Loss of all scalp hair.

Alveolar capillary dysplasia with misalignment of pulmonary veins (ACD/MPV) is a disorder affecting the development of the lungs and their blood vessels. The disorder affects the millions of small air sacs (alveoli) in the lungs and the tiny blood vessels (capillaries) in the alveoli. It is through these alveolar capillaries that inhaled oxygen enters the bloodstream for distribution throughout the body and carbon dioxide leaves the bloodstream to be exhaled.\n\nIn ACD/MPV, the alveolar capillaries fail to develop normally. The number of capillaries is drastically reduced, and existing capillaries are improperly positioned within the walls of the alveoli. These abnormalities in capillary number and location impede the exchange of oxygen and carbon dioxide.\n\nOther abnormalities of the blood vessels in the lungs also occur in ACD/MPV. The veins that carry blood from the lungs into the heart (pulmonary veins) are improperly positioned and may be abnormally bundled together with arteries that carry blood from the heart to the lungs (pulmonary arteries). The muscle tissue in the walls of the pulmonary arteries may be overgrown, resulting in thicker artery walls and a narrower channel. These changes restrict normal blood flow, which causes high blood pressure in the pulmonary arteries (pulmonary hypertension) and requires the heart to pump harder.\n\nMost infants with ACD/MPV are born with additional abnormalities. These may include abnormal twisting (malrotation) of the large intestine or other malformations of the gastrointestinal tract. Cardiovascular and genitourinary abnormalities are also common in affected individuals.\n\nInfants with ACD/MPV typically develop respiratory distress within a few minutes to a few hours after birth. They experience shortness of breath and cyanosis, which is a bluish appearance of the skin, mucous membranes, or the area underneath the fingernails caused by a lack of oxygen in the blood. Without lung transplantation, infants with ACD/MPV have not been known to survive past one year of age, and most affected infants live only a few weeks.

Papilledema refers to edema (swelling) of the optic disc secondary to any factor which increases cerebral spinal fluid pressure.