bowang0911/MedQuAD huggingface dataset:
Malonyl-CoA decarboxylase deficiency is a condition that prevents the body from converting certain fats to energy. The signs and symptoms of this disorder typically appear in early childhood. Almost all affected children have delayed development. Additional signs and symptoms can include weak muscle tone (hypotonia), seizures, diarrhea, vomiting, and low blood sugar (hypoglycemia). A heart condition called cardiomyopathy, which weakens and enlarges the heart muscle, is another common feature of malonyl-CoA decarboxylase deficiency.
Mutations in the MLYCD gene cause malonyl-CoA decarboxylase deficiency. The MLYCD gene provides instructions for making an enzyme called malonyl-CoA decarboxylase. Within cells, this enzyme helps regulate the formation and breakdown of a group of fats called fatty acids. Many tissues, including the heart muscle, use fatty acids as a major source of energy.  Mutations in the MLYCD gene reduce or eliminate the function of malonyl-CoA decarboxylase. A shortage of this enzyme disrupts the normal balance of fatty acid formation and breakdown in the body. As a result, fatty acids cannot be converted to energy, which can lead to characteristic features of this disorder including low blood sugar and cardiomyopathy. Byproducts of fatty acid processing build up in tissues, which also contributes to the signs and symptoms of malonyl-CoA decarboxylase deficiency.
These resources address the diagnosis or management of malonyl-CoA decarboxylase deficiency:  - Baby's First Test  - Genetic Testing Registry: Deficiency of malonyl-CoA decarboxylase   These resources from MedlinePlus offer information about the diagnosis and management of various health conditions:  - Diagnostic Tests  - Drug Therapy  - Surgery and Rehabilitation  - Genetic Counseling   - Palliative Care
Sick sinus syndrome (also known as sinus node dysfunction) is a group of related heart conditions that can affect how the heart beats. "Sick sinus" refers to the sino-atrial (SA) node, which is an area of specialized cells in the heart that functions as a natural pacemaker. The SA node generates electrical impulses that start each heartbeat. These signals travel from the SA node to the rest of the heart, signaling the heart (cardiac) muscle to contract and pump blood. In people with sick sinus syndrome, the SA node does not function normally. In some cases, it does not produce the right signals to trigger a regular heartbeat. In others, abnormalities disrupt the electrical impulses and prevent them from reaching the rest of the heart.  Sick sinus syndrome tends to cause the heartbeat to be too slow (bradycardia), although occasionally the heartbeat is too fast (tachycardia). In some cases, the heartbeat rapidly switches from being too fast to being too slow, a condition known as tachycardia-bradycardia syndrome. Symptoms related to abnormal heartbeats can include dizziness, light-headedness, fainting (syncope), a sensation of fluttering or pounding in the chest (palpitations), and confusion or memory problems. During exercise, many affected individuals experience chest pain, difficulty breathing, or excessive tiredness (fatigue). Once symptoms of sick sinus syndrome appear, they usually worsen with time. However, some people with the condition never experience any related health problems.  Sick sinus syndrome occurs most commonly in older adults, although it can be diagnosed in people of any age. The condition increases the risk of several life-threatening problems involving the heart and blood vessels. These include a heart rhythm abnormality called atrial fibrillation, heart failure, cardiac arrest, and stroke.
Sick sinus syndrome can result from genetic or environmental factors. In many cases, the cause of the condition is unknown.  Genetic changes are an uncommon cause of sick sinus syndrome. Mutations in two genes, SCN5A and HCN4, have been found to cause the condition in a small number of families. These genes provide instructions for making proteins called ion channels that transport positively charged atoms (ions) into cardiac cells, including cells that make up the SA node. The flow of these ions is essential for creating the electrical impulses that start each heartbeat and coordinate contraction of the cardiac muscle. Mutations in these genes reduce the flow of ions, which alters the SA node's ability to create and spread electrical signals. These changes lead to abnormal heartbeats and the other symptoms of sick sinus syndrome.  A particular variation in another gene, MYH6, appears to increase the risk of developing sick sinus syndrome. The protein produced from the MYH6 gene forms part of a larger protein called myosin, which generates the mechanical force needed for cardiac muscle to contract. Researchers believe that the MYH6 gene variation changes the structure of myosin, which can affect cardiac muscle contraction and increase the likelihood of developing an abnormal heartbeat.  More commonly, sick sinus syndrome is caused by other factors that alter the structure or function of the SA node. These include a variety of heart conditions, other disorders such as muscular dystrophy, abnormal inflammation, or a shortage of oxygen (hypoxia). Certain medications, such as drugs given to treat abnormal heart rhythms or high blood pressure, can also disrupt SA node function. One of the most common causes of sick sinus syndrome in children is trauma to the SA node, such as damage that occurs during heart surgery.  In older adults, sick sinus syndrome is often associated with age-related changes in the heart. Over time, the SA node may harden and develop scar-like damage (fibrosis) that prevents it from working properly.
Most cases of sick sinus syndrome are not inherited. They are described as sporadic, which means they occur in people with no history of the disorder in their family.  When sick sinus syndrome results from mutations in the HCN4 gene, it has an autosomal dominant pattern of inheritance. Autosomal dominant inheritance means that one copy of the altered gene in each cell is sufficient to cause the disorder. In most cases, an affected person has one parent with the condition.  When sick sinus syndrome is caused by mutations in the SCN5A gene, it is inherited in an autosomal recessive pattern. Autosomal recessive inheritance means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.
These resources address the diagnosis or management of sick sinus syndrome:  - Cleveland Clinic: Management of Arrhythmias  - Genetic Testing Registry: Sick sinus syndrome 1, autosomal recessive  - Genetic Testing Registry: Sick sinus syndrome 2, autosomal dominant  - Genetic Testing Registry: Sick sinus syndrome 3, susceptibility to  - National Heart Lung and Blood Institute: What Is a Pacemaker?   These resources from MedlinePlus offer information about the diagnosis and management of various health conditions:  - Diagnostic Tests  - Drug Therapy  - Surgery and Rehabilitation  - Genetic Counseling   - Palliative Care
GM3 synthase deficiency is characterized by recurrent seizures (epilepsy) and problems with brain development. Within the first few weeks after birth, affected infants become irritable and develop feeding difficulties and vomiting that prevent them from growing and gaining weight at the usual rate. Seizures begin within the first year of life and worsen over time. Multiple types of seizures are possible, including generalized tonic-clonic seizures (also known as grand mal seizures), which cause muscle rigidity, convulsions, and loss of consciousness. Some affected children also experience prolonged episodes of seizure activity called nonconvulsive status epilepticus. The seizures associated with GM3 synthase deficiency tend to be resistant (refractory) to treatment with antiseizure medications.  GM3 synthase deficiency profoundly disrupts brain development. Most affected children have severe intellectual disability and do not develop skills such as reaching for objects, speaking, sitting without support, or walking. Some have involuntary twisting or jerking movements of the arms that are described as choreoathetoid. Although affected infants can likely see and hear at birth, vision and hearing become impaired as the disease worsens. It is unknown how long people with GM3 synthase deficiency usually survive.  Some affected individuals have changes in skin coloring (pigmentation), including dark freckle-like spots on the arms and legs and light patches on the arms, legs, and face. These changes appear in childhood and may become more or less apparent over time. The skin changes do not cause any symptoms, but they can help doctors diagnose GM3 synthase deficiency in children who also have seizures and delayed development.
Mutations in the ST3GAL5 gene have been found to cause GM3 synthase deficiency. This gene provides instructions for making an enzyme called GM3 synthase, which carries out a chemical reaction that is the first step in the production of molecules called gangliosides. These molecules are present in cells and tissues throughout the body, and they are particularly abundant in the nervous system. Although their exact functions are unclear, gangliosides appear to be important for normal brain development and function.  ST3GAL5 gene mutations prevent the production of any functional GM3 synthase. Without this enzyme, cells cannot produce gangliosides normally. It is unclear how a loss of this enzyme leads to the signs and symptoms of GM3 synthase deficiency. Researchers are working to determine whether it is the lack of gangliosides or a buildup of compounds used to make gangliosides, or both, that underlies the seizures and other problems with brain development that occur in this condition. The connection between a shortage of GM3 synthase and changes in skin pigmentation is also unknown.
These resources address the diagnosis or management of GM3 synthase deficiency:  - American Epilepsy Society: Find a Doctor  - Clinic for Special Children (Strasburg, Pennsylvania)  - Genetic Testing Registry: Amish infantile epilepsy syndrome   These resources from MedlinePlus offer information about the diagnosis and management of various health conditions:  - Diagnostic Tests  - Drug Therapy  - Surgery and Rehabilitation  - Genetic Counseling   - Palliative Care
Myhre syndrome is a condition with features affecting many systems and functions of the body.  People with Myhre syndrome usually have delayed development of language and motor skills such as crawling and walking. Most have intellectual disability that ranges from mild to moderate. Some have behavioral issues such as features of autism or related developmental disorders affecting communication and social interaction.  People with Myhre syndrome often have hearing loss, which can be caused by changes in the inner ear (sensorineural deafness), changes in the middle ear (conductive hearing loss), or both (mixed hearing loss).  Growth is reduced in people with this disorder, beginning before birth and continuing through adolescence. Affected individuals have a low birth weight and are generally shorter than about 97 percent of their peers throughout life.  People with Myhre syndrome typically have stiffness of the skin and are usually described as having a muscular appearance. Skeletal abnormalities associated with this disorder include thickening of the skull bones, flattened bones of the spine (platyspondyly), broad ribs, underdevelopment of the winglike structures of the pelvis (hypoplastic iliac wings), and unusually short fingers and toes (brachydactyly). Affected individuals often have joint problems (arthropathy), including stiffness and limited mobility.  Typical facial features in people with Myhre syndrome include narrow openings of the eyelids (short palpebral fissures), a shortened distance between the nose and upper lip (a short philtrum), a sunken appearance of the middle of the face (midface hypoplasia), a small mouth with a thin upper lip, and a protruding jaw (prognathism). Some affected individuals also have an opening in the roof of the mouth (a cleft palate), a split in the lip (a cleft lip), or both.  Other features that occur in some people with this disorder include constriction of the throat (laryngotracheal stenosis), high blood pressure (hypertension), heart or eye abnormalities, and in males, undescended testes (cryptorchidism).  A disorder sometimes called laryngotracheal stenosis, arthropathy, prognathism, and short stature (LAPS) syndrome is now generally considered to be the same condition as Myhre syndrome because it has similar symptoms and the same genetic cause.
Mutations in the SMAD4 gene cause Myhre syndrome. The SMAD4 gene provides instructions for making a protein involved in transmitting chemical signals from the cell surface to the nucleus. This signaling pathway, called the transforming growth factor beta (TGF-) pathway, allows the environment outside the cell to affect how the cell produces other proteins. As part of this pathway, the SMAD4 protein interacts with other proteins to control the activity of particular genes. These genes influence many areas of development.  Some researchers believe that the SMAD4 gene mutations that cause Myhre syndrome impair the ability of the SMAD4 protein to attach (bind) properly with the other proteins involved in the signaling pathway. Other studies have suggested that these mutations result in an abnormally stable SMAD4 protein that remains active in the cell longer. Changes in SMAD4 binding or availability may result in abnormal signaling in many cell types, which affects development of several body systems and leads to the signs and symptoms of Myhre syndrome.
These resources address the diagnosis or management of Myhre syndrome:  - Centers for Disease Control and Prevention: Types of Hearing Loss  - Genetic Testing Registry: Myhre syndrome  - National Institute on Deafness and Other Communication Disorders: Communication Considerations for Parents of Deaf and Hard-of-Hearing Children   These resources from MedlinePlus offer information about the diagnosis and management of various health conditions:  - Diagnostic Tests  - Drug Therapy  - Surgery and Rehabilitation  - Genetic Counseling   - Palliative Care
ADCY5-related dyskinesia is a movement disorder; the term "dyskinesia" refers to abnormal involuntary movements. The abnormal movements that occur in ADCY5-related dyskinesia typically appear as sudden (paroxysmal) jerks, twitches, tremors, muscle tensing (dystonia), or writhing (choreiform) movements, and can affect the limbs, neck, and face.  The abnormal movements associated with ADCY5-related dyskinesia usually begin between infancy and late adolescence. They can occur continually during waking hours and in some cases also during sleep. Severely affected infants may experience weak muscle tone (hypotonia) and delay in development of motor skills such as crawling and walking; these individuals may have difficulties with activities of daily living and may eventually require a wheelchair. In more mildly affected individuals, the condition has little impact on walking and other motor skills, although the abnormal movements can lead to clumsiness or difficulty with social acceptance in school or other situations.  In some people with ADCY5-related dyskinesia, the disorder is generally stable throughout their lifetime. In others, it slowly gets worse (progresses) in both frequency and severity before stabilizing or even improving in middle age. Anxiety, fatigue, and other stress can temporarily increase the severity of the signs and symptoms of ADCY5-related dyskinesia, while some affected individuals may experience remission periods of days or weeks without abnormal movements. Life expectancy and intelligence are unaffected by this disorder.
As its name suggests, ADCY5-related dyskinesia is caused by mutations in the ADCY5 gene. This gene provides instructions for making an enzyme called adenylate cyclase 5. This enzyme helps convert a molecule called adenosine triphosphate (ATP) to another molecule called cyclic adenosine monophosphate (cAMP). ATP is a molecule that supplies energy for cells' activities, including muscle contraction, and cAMP is involved in signaling for many cellular functions. Some ADCY5 gene mutations that cause ADCY5-related dyskinesia are thought to increase adenylate cyclase 5 enzyme activity and the level of cAMP within cells. Others prevent production of adenylate cyclase 5. It is unclear how either type of mutation leads to the abnormal movements that occur in this disorder.
These resources address the diagnosis or management of ADCY5-related dyskinesia:  - Gene Review: Gene Review: ADCY5-Related Dyskinesia  - Genetic Testing Registry: Dyskinesia, familial, with facial myokymia  - National Ataxia Foundation: Movement Disorder Clinics   These resources from MedlinePlus offer information about the diagnosis and management of various health conditions:  - Diagnostic Tests  - Drug Therapy  - Surgery and Rehabilitation  - Genetic Counseling   - Palliative Care
Shwachman-Diamond syndrome is an inherited condition that affects many parts of the body, particularly the bone marrow, pancreas, and skeletal system.  The major function of bone marrow is to produce new blood cells. These include red blood cells, which carry oxygen to the body's tissues; white blood cells, which fight infection; and platelets, which are necessary for normal blood clotting. In Shwachman-Diamond syndrome, the bone marrow malfunctions and does not make some or all types of white blood cells. A shortage of neutrophils, the most common type of white blood cell, causes a condition called neutropenia. Most people with Shwachman-Diamond syndrome have at least occasional episodes of neutropenia, which makes them more vulnerable to infections such as pneumonia, recurrent ear infections (otitis media), and skin infections. Less commonly, bone marrow abnormalities lead to a shortage of red blood cells (anemia), which causes fatigue and weakness, or a reduction in the amount of platelets (thrombocytopenia), which can result in easy bruising and abnormal bleeding.  People with Shwachman-Diamond syndrome have an increased risk of several serious complications related to their malfunctioning bone marrow. Specifically, they have a higher-than-average chance of developing myelodysplastic syndrome (MDS) and aplastic anemia, which are disorders that affect blood cell production, and a cancer of blood-forming tissue known as acute myeloid leukemia (AML).  Shwachman-Diamond syndrome also affects the pancreas, which is an organ that plays an essential role in digestion. One of this organ's main functions is to produce enzymes that help break down and use the nutrients from food. In most infants with Shwachman-Diamond syndrome, the pancreas does not produce enough of these enzymes. This condition is known as pancreatic insufficiency. Infants with pancreatic insufficiency have trouble digesting food and absorbing nutrients that are needed for growth. As a result, they often have fatty, foul-smelling stools (steatorrhea); are slow to grow and gain weight (failure to thrive); and experience malnutrition. Pancreatic insufficiency often improves with age in people with Shwachman-Diamond syndrome.  Skeletal abnormalities are another common feature of Shwachman-Diamond syndrome. Many affected individuals have problems with bone formation and growth, most often affecting the hips and knees. Low bone density is also frequently associated with this condition. Some infants are born with a narrow rib cage and short ribs, which can cause life-threatening problems with breathing. The combination of skeletal abnormalities and slow growth results in short stature in most people with this disorder.  The complications of this condition can affect several other parts of the body, including the liver, heart, endocrine system (which produces hormones), eyes, teeth, and skin. Additionally, studies suggest that Shwachman-Diamond syndrome may be associated with delayed speech and the delayed development of motor skills such as sitting, standing, and walking.
Mutations in the SBDS gene have been identified in about 90 percent of people with the characteristic features of Shwachman-Diamond syndrome. This gene provides instructions for making a protein whose function is unknown, although it is active in cells throughout the body. Researchers suspect that the SBDS protein may play a role in processing RNA (a molecule that is a chemical cousin of DNA). This protein may also be involved in building ribosomes, which are cellular structures that process the cell's genetic instructions to create proteins. It is unclear how SBDS mutations lead to the major signs and symptoms of Shwachman-Diamond syndrome.  In cases where no SBDS mutation is found, the cause of this disorder is unknown.
These resources address the diagnosis or management of Shwachman-Diamond syndrome:  - Gene Review: Gene Review: Shwachman-Diamond Syndrome  - Genetic Testing Registry: Shwachman syndrome  - MedlinePlus Encyclopedia: Malabsorption   These resources from MedlinePlus offer information about the diagnosis and management of various health conditions:  - Diagnostic Tests  - Drug Therapy  - Surgery and Rehabilitation  - Genetic Counseling   - Palliative Care
Essential tremor is a movement disorder that causes involuntary, rhythmic shaking (tremor), especially in the hands. It is distinguished from tremor that results from other disorders or known causes, such as Parkinson disease or head trauma. Essential tremor usually occurs alone, without other neurological signs or symptoms. However, some experts think that essential tremor can include additional features, such as mild balance problems.  Essential tremor usually occurs with movements and can occur during many different types of activities, such as eating, drinking, or writing. Essential tremor can also occur when the muscles are opposing gravity, such as when the hands are extended. It is usually not evident at rest.  In addition to the hands and arms, muscles of the trunk, face, head, and neck may also exhibit tremor in this disorder; the legs and feet are less often involved. Head tremor may appear as a "yes-yes" or "no-no" movement while the affected individual is seated or standing. In some people with essential tremor, the tremor may affect the voice (vocal tremor).  Essential tremor does not shorten the lifespan. However, it may interfere with fine motor skills such as using eating utensils, writing, shaving, or applying makeup, and in some cases these and other activities of daily living can be greatly impaired. Symptoms of essential tremor may be aggravated by emotional stress, anxiety, fatigue, hunger, caffeine, cigarette smoking, or temperature extremes.  Essential tremor may appear at any age but is most common in the elderly. Some studies have suggested that people with essential tremor have a higher than average risk of developing neurological conditions including Parkinson disease or sensory problems such as hearing loss, especially in individuals whose tremor appears after age 65.
Essential tremor is a common disorder, affecting up to 10 million people in the United States. Estimates of its prevalence vary widely because several other disorders, as well as other factors such as certain medications, can result in similar tremors. In addition, mild cases are often not brought to medical attention, or may not be detected in clinical exams that do not include the particular circumstances in which an individual's tremor occurs. Severe cases are often misdiagnosed as Parkinson disease.