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Each of the heart defects associated with CCHD affects the flow of blood into, out of, or through the heart. Some of the heart defects involve structures within the heart itself, such as the two lower chambers of the heart (the ventricles) or the valves that control blood flow through the heart. Others affect the structure of the large blood vessels leading into and out of the heart (including the aorta and pulmonary artery). Still others involve a combination of these structural abnormalities.

Some people with treated CCHD have few related health problems later in life. However, long-term effects of CCHD can include delayed development and reduced stamina during exercise. Adults with these heart defects have an increased risk of abnormal heart rhythms, heart failure, sudden cardiac arrest, stroke, and premature death.

Although babies with CCHD may appear healthy for the first few hours or days of life, signs and symptoms soon become apparent. These can include an abnormal heart sound during a heartbeat (heart murmur), rapid breathing (tachypnea), low blood pressure (hypotension), low levels of oxygen in the blood (hypoxemia), and a blue or purple tint to the skin caused by a shortage of oxygen (cyanosis). If untreated, CCHD can lead to shock, coma, and death. However, most people with CCHD now survive past infancy due to improvements in early detection, diagnosis, and treatment.

Critical congenital heart disease (CCHD) is a term that refers to a group of serious heart defects that are present from birth. These abnormalities result from problems with the formation of one or more parts of the heart during the early stages of embryonic development. CCHD prevents the heart from pumping blood effectively or reduces the amount of oxygen in the blood. As a result, organs and tissues throughout the body do not receive enough oxygen, which can lead to organ damage and life-threatening complications. Individuals with CCHD usually require surgery soon after birth.

People with CCHD have one or more specific heart defects. The heart defects classified as CCHD include coarctation of the aorta, double-outlet right ventricle, D-transposition of the great arteries, Ebstein anomaly, hypoplastic left heart syndrome, interrupted aortic arch, pulmonary atresia with intact septum, single ventricle, total anomalous pulmonary venous connection, tetralogy of Fallot, tricuspid atresia, and truncus arteriosus. [from MedlinePlus Genetics]

The severity of congenital hyperinsulinism varies widely among affected individuals, even among members of the same family. About 60 percent of infants with this condition experience a hypoglycemic episode within the first month of life. Other affected children develop hypoglycemia by early childhood. Unlike typical episodes of hypoglycemia, which occur most often after periods without food (fasting) or after exercising, episodes of hypoglycemia in people with congenital hyperinsulinism can also occur after eating.

Congenital hyperinsulinism is a condition that causes individuals to have abnormally high levels of insulin. Insulin is a hormone that helps control levels of blood glucose, also called blood sugar. People with this condition have frequent episodes of low blood glucose (hypoglycemia). In infants and young children, these episodes are characterized by a lack of energy (lethargy), irritability, or difficulty feeding. Repeated episodes of low blood glucose increase the risk for serious complications such as breathing difficulties, seizures, intellectual disability, vision loss, brain damage, and coma. [from MedlinePlus Genetics]

Leukoencephalopathy with vanishing white matter-5 (VWM5) is a chronic and progressive autosomal recessive leukoencephalopathy characterized by neurologic deterioration usually beginning in late infancy or early childhood; however, juvenile- and adult-onset cases have been reported. Neurologic signs include cerebellar ataxia, spasticity, and relatively preserved mental abilities. The disease is chronic and progressive with, in most individuals, additional episodes of rapid deterioration following febrile infections or minor head trauma. Death occurs after a variable period of a few years to a few decades, usually following an episode of fever and coma. Magnetic resonance imaging (MRI) and magnetic resonance spectroscopy are diagnostic and show a diffuse abnormality of the cerebral white matter beginning in the presymptomatic stage, with increasing amounts of the abnormal white matter vanishing and being replaced by cerebrospinal fluid; autopsy confirms these findings (summary by Leegwater et al., 2001). Ovarian dysgenesis may be present in affected females (Fogli et al., 2003). For a discussion of genetic heterogeneity of VWM, see 603896. Cree Leukoencephalopathy An infantile leukoencephalopathy among the native Cree and Chippewayan indigenous population in Northern Quebec and Manitoba results from homozygosity for an arg195-to-his (R195H; 603945.0005) mutation in the EIF2B5 gene. These patients have disease onset between 3 and 9 months of age, with death in 100% by 21 months of age. [from OMIM]

Preeclampsia is a complication of pregnancy in which affected women develop high blood pressure (hypertension); they can also have abnormally high levels of protein in their urine (proteinuria). This condition usually occurs in the last few months of pregnancy and often requires early delivery of the infant. However, this condition can also appear shortly after giving birth (postpartum preeclampsia).

Many women with mild preeclampsia do not feel ill, and the condition is often first detected through blood pressure and urine testing in their doctor's office. In addition to hypertension and proteinuria, signs and symptoms of preeclampsia can include excessive swelling (edema) of the face or hands and a weight gain of more than 3 to 5 pounds in a week due to fluid retention. Affected women may also experience headaches, dizziness, irritability, shortness of breath, a decrease in urination, upper abdominal pain, and nausea or vomiting. Vision changes may develop, including flashing lights or spots, increased sensitivity to light (photophobia), blurry vision, or temporary blindness.

In many cases, symptoms of preeclampsia go away within a few days after the baby is born. In severe cases, however, preeclampsia can damage the mother's organs, such as the heart, liver, and kidneys, and can lead to life-threatening complications. Extremely high blood pressure in the mother can cause bleeding in the brain (hemorrhagic stroke). The effects of high blood pressure on the brain (hypertensive encephalopathy) may also result in seizures. If seizures occur, the condition is considered to have worsened to eclampsia, which can result in coma. About 1 in 200 women with untreated preeclampsia develop eclampsia. Eclampsia can also develop without any obvious signs of preeclampsia.

Between 10 and 20 percent of women with severe preeclampsia develop another potentially life-threatening complication called HELLP syndrome. HELLP stands for hemolysis (premature red blood cell breakdown), elevated liver enzyme levels, and low platelets (cells involved in blood clotting), which are the key features of this condition.

Women who have had preeclampsia have approximately twice the lifetime risk of heart disease and stroke than do women in the general population. Researchers suggest that preeclampsia, heart disease, and stroke may share common risk factors. Women who have diseases such as obesity, hypertension, heart disease, diabetes, or kidney disease before they become pregnant have an increased risk of developing preeclampsia. Preeclampsia is most likely to occur in a woman's first pregnancy, although it can occur in subsequent pregnancies, particularly in women with other health conditions.

Severe preeclampsia can also affect the fetus, with impairment of blood and oxygen flow leading to growth problems or stillbirth. Infants delivered early due to preeclampsia may have complications associated with prematurity, such as breathing problems caused by underdeveloped lungs. [from MedlinePlus Genetics]

Severe preeclampsia can also affect the fetus, with impairment of blood and oxygen flow leading to growth problems or stillbirth. Infants delivered early due to preeclampsia may have complications associated with prematurity, such as breathing problems caused by underdeveloped lungs.

Women who have had preeclampsia have approximately twice the lifetime risk of heart disease and stroke than do women in the general population. Researchers suggest that preeclampsia, heart disease, and stroke may share common risk factors. Women who have diseases such as obesity, hypertension, heart disease, diabetes, or kidney disease before they become pregnant have an increased risk of developing preeclampsia. Preeclampsia is most likely to occur in a woman's first pregnancy, although it can occur in subsequent pregnancies, particularly in women with other health conditions.

Between 10 and 20 percent of women with severe preeclampsia develop another potentially life-threatening complication called HELLP syndrome. HELLP stands for hemolysis (premature red blood cell breakdown), elevated liver enzyme levels, and low platelets (cells involved in blood clotting), which are the key features of this condition.

In many cases, symptoms of preeclampsia go away within a few days after the baby is born. In severe cases, however, preeclampsia can damage the mother's organs, such as the heart, liver, and kidneys, and can lead to life-threatening complications. Extremely high blood pressure in the mother can cause bleeding in the brain (hemorrhagic stroke). The effects of high blood pressure on the brain (hypertensive encephalopathy) may also result in seizures. If seizures occur, the condition is considered to have worsened to eclampsia, which can result in coma. About 1 in 200 women with untreated preeclampsia develop eclampsia. Eclampsia can also develop without any obvious signs of preeclampsia.

Many women with mild preeclampsia do not feel ill, and the condition is often first detected through blood pressure and urine testing in their doctor's office. In addition to hypertension and proteinuria, signs and symptoms of preeclampsia can include excessive swelling (edema) of the face or hands and a weight gain of more than 3 to 5 pounds in a week due to fluid retention. Affected women may also experience headaches, dizziness, irritability, shortness of breath, a decrease in urination, upper abdominal pain, and nausea or vomiting. Vision changes may develop, including flashing lights or spots, increased sensitivity to light (photophobia), blurry vision, or temporary blindness.

Preeclampsia is a complication of pregnancy in which affected women develop high blood pressure (hypertension); they can also have abnormally high levels of protein in their urine (proteinuria). This condition usually occurs in the last few months of pregnancy and often requires early delivery of the infant. However, this condition can also appear shortly after giving birth (postpartum preeclampsia). [from MedlinePlus Genetics]

Type 1 diabetes is a disorder characterized by abnormally high levels of blood glucose, also called blood sugar. In this form of diabetes, specialized cells in the pancreas called beta cells stop producing insulin. Insulin controls how much glucose (a type of sugar) is passed from the blood into cells for conversion to energy. Lack of insulin results in the inability to use glucose for energy or to control the amount of glucose in the blood.

Type 1 diabetes can occur at any age, from early childhood to late adulthood. The first signs and symptoms of the disorder are caused by high blood glucose and may include frequent urination (polyuria), excessive thirst (polydipsia), fatigue, blurred vision, tingling or loss of feeling in the hands and feet, and weight loss. These symptoms may recur during the course of the disorder if blood glucose is not well controlled by insulin replacement therapy. Improper control can also cause blood glucose levels to become too low (hypoglycemia). This may occur when the body's needs change, such as during exercise or if eating is delayed. Hypoglycemia can cause headache, dizziness, hunger, shaking, sweating, weakness, and agitation.

Over many years, the chronic high blood glucose associated with diabetes may cause damage to blood vessels and nerves, leading to complications affecting many organs and tissues. The retina, which is the light-sensitive tissue at the back of the eye, can be damaged (diabetic retinopathy), leading to vision loss and eventual blindness. Kidney damage (diabetic nephropathy) may also occur and can lead to kidney failure and end-stage renal disease (ESRD). Pain, tingling, and loss of normal sensation (diabetic neuropathy) often occur, especially in the feet. Impaired circulation and absence of the normal sensations that prompt reaction to injury can result in permanent damage to the feet; in severe cases, the damage can lead to amputation. People with type 1 diabetes are also at increased risk of heart attacks, strokes, and problems with urinary and sexual function.

Uncontrolled type 1 diabetes can lead to a life-threatening complication called diabetic ketoacidosis. Without insulin, cells cannot take in glucose. A lack of glucose in cells prompts the liver to try to compensate by releasing more glucose into the blood, and blood glucose can become extremely high. The cells, unable to use the glucose in the blood for energy, respond by using fats instead. Breaking down fats to obtain energy produces waste products called ketones, which can build up to toxic levels in people with type 1 diabetes, resulting in diabetic ketoacidosis. Affected individuals may begin breathing rapidly; develop a fruity odor in the breath; and experience nausea, vomiting, facial flushing, stomach pain, and dryness of the mouth (xerostomia). In severe cases, diabetic ketoacidosis can lead to coma and death. [from MedlinePlus Genetics]

Systemic primary carnitine deficiency (CDSP) is a disorder of the carnitine cycle that results in defective fatty acid oxidation. It encompasses a broad clinical spectrum including the following: Metabolic decompensation in infancy typically presenting between age three months and two years with episodes of hypoketotic hypoglycemia, poor feeding, irritability, lethargy, hepatomegaly, elevated liver transaminases, and hyperammonemia triggered by fasting or common illnesses such as upper respiratory tract infection or gastroenteritis. Childhood myopathy involving heart and skeletal muscle with onset between age two and four years. Pregnancy-related decreased stamina or exacerbation of cardiac arrhythmia. Fatigability in adulthood. Absence of symptoms. The latter two categories often include mothers diagnosed with CDSP after newborn screening has identified low carnitine levels in their infants. [from GeneReviews]

3-Methylcrotonylglycinuria is an autosomal recessive disorder of leucine catabolism. The clinical phenotype is highly variable, ranging from neonatal onset with severe neurologic involvement to asymptomatic adults. There is a characteristic organic aciduria with massive excretion of 3-hydroxyisovaleric acid and 3-methylcrotonylglycine, usually in combination with a severe secondary carnitine deficiency. MCC activity in extracts of cultured fibroblasts of patients is usually less than 2% of control (summary by Baumgartner et al., 2001). Also see 3-methylcrotonylglycinuria I (MCC1D; 210200), caused by mutation in the alpha subunit of 3-methylcrotonyl-CoA carboxylase (MCCC1; 609010). [from OMIM]

Mitochondrial complex III deficiency, nuclear type 8, is an autosomal recessive disorder characterized by progressive neurodegeneration with onset in childhood. Affected individuals may have normal or delayed early development, and often have episodic acute neurologic decompensation and regression associated with febrile illnesses. The developmental regression results in variable intellectual disability and motor deficits, such as hypotonia, axial hypertonia, and spasticity; some patients may lose the ability to walk independently. Laboratory studies show increased serum lactate and isolated deficiency of mitochondrial complex III in skeletal muscle and fibroblasts. Brain imaging shows a characteristic pattern of multifocal small cystic lesions in the periventricular and deep cerebral white matter (summary by Dallabona et al., 2016). For a discussion of genetic heterogeneity of mitochondrial complex III deficiency, see MC3DN1 (124000). [from OMIM]