How does the gene for hypokalemic periodic paralysis present?

What sex is more at risk for hypokalemic periodic paralysis?

The gene for hypokalemic PP is present equally in both sexes, but leads to noticeable symptoms more often in men than in women.

What does the normal gene responsible for hypokalemic periodic paralysis responsible for?

The normal gene is responsible for a muscle protein controlling the flow of calcium during muscle contraction.

How does the gene for hyperkalemic periodic paralysis present?

The gene for hyperkalemic PP affects virtually all who inherit it, with no difference in male-vs.-female expression.

What determines if the gene for periodic paralysis is passed on?

The gene for periodic paralysis is passed on through inheritance from parents to their children. It is determined by the specific genetic mutation present in the affected individual's DNA. Offspring have a 50% chance of inheriting the gene if one parent carries the mutation.

What does the normal gene responsible for hyperkalemic periodic paralysis responsible for?

The normal gene is responsible for a muscle protein controlling the flow of sodium during muscle contraction.

What gender has a greater genetic risk for hyperkalemic periodic paralysis?

The gene for hyperkalemic PP affects virtually all who inherit it, with no difference in male-vs.-female expression.

What is the term for when two or more versions of a gene are present in an organism?

The term for when two or more versions of a gene are present in an organism is called "gene polymorphism."

Hypokalemic periodic paralysis?

DefinitionHypokalemic periodic paralysis is an inherited disorder that causes occasional episodes of muscle weakness.It is one of a group of genetic disorders that includes hyperkalemic periodic paralysis and thyrotoxic periodic paralysis.Alternative NamesPeriodic paralysis - hypokalemicCauses, incidence, and risk factorsHypokalemic periodic paralysis is a condition in which a person has episodes of muscle weakness and sometimes severe paralysis.The condition is congenital, which means it is present from birth. In most cases, it is passed down through families (inherited) as an autosomal dominant disorder. That means only one parent needs to pass the gene related to this condition on to you in order for you to be affected.Occasionally, the condition may be the result of a genetic problem that is not inherited.Unlike other forms of periodic paralysis, persons with congenital hypokalemic periodic paralysis have normal thyroid function and very low blood levels of potassium during episodes of weakness. This results from potassium moving from the blood into muscle cells in an abnormal way.Risks include having other family members with periodic paralysis. The risk is slightly higher in Asian men who also have thyroid disorders.Disorders that cause intermittent episodes of paralysis as their primary effect are uncommon. Hypokalemic periodic paralysis occurs in approximately 1 out of 100,000 people.SymptomsThe disorder involves attacks of muscle weakness or loss of muscle movement (paralysis) that come and go. Initially, there is normal muscle strength between attacks.Attacks usually begin in adolescence, but they can occur before age 10. Attacks that do not begin until adulthood are rare in people with hypokalemic periodic paralysis and are usually caused by other disorders.How often the attacks occur varies. Some people have attacks every day, while others have them once a year. Episodes of muscle weakness usually last between a few hours and a day.The weakness or paralysis:Most commonly is located at the shoulders and hipsMay also affect the arms, legs, muscles of the eyes, and muscles that help you breathe and swallowOccurs intermittentlyMost commonly occurs on awakeningMost commonly occurs after sleep or restIs rare during exercise, but may be triggered by rest after exerciseMay be triggered by heavy, high-carbohydrate, high-salt meals or alcohol consumptionUsually lasts 3 - 24 hoursOther symptoms may include:Eyelid myotonia (a condition in which after opening and closing the eyes, the patient cannot open them for a short time)Note: The patient's thinking remains alert during attacks.Signs and testsBetween attacks, a physical examination shows nothing abnormal. Before an attack, there may be leg stiffness or heaviness in the legs.During an attack of muscle weakness, the blood potassium level is low. This confirms the diagnosis. There is no decrease in total body potassium, and blood potassium levels are normal between attacks.During an attack, muscle reflexes may be decreased or absent, and muscles go limp rather than staying stiff. The muscle groups near the body, such as shoulders and hips, are involved more often than the arms and legs.An ECG or heart tracing may be abnormal during attacks.An EMG or muscle tracing is usually normal between attacks and abnormal during attacks.A muscle biopsymay show abnormalities.TreatmentMuscle weakness that involves the breathing or swallowing muscles is an emergency situation. Dangerous heart arrhythmias may also occur during attacks.The goals of treatment are relief of symptoms and prevention of further attacks.Potassium that is given during an attack may stop the attack. It is preferred that potassium be given by mouth, but if weakness is severe, potassium may need to be given through a vein (IV). Note: Potassium, especially intravenous potassium, should be given with caution, especially in individuals with kidney disease.Taking potassium supplements will not prevent attacks.Avoiding alcohol and eating a low-carbohydrate diet may help.A medicine called acetazolamide prevents attacks in many cases. If you take this medicine, your doctor may tell you to also take potassium supplements because acetazolamide may cause your body to lose potassium.Triamterene or spironolactone may help to prevent attacks in people who do not respond to acetazolamide.Expectations (prognosis)Hypokalemic periodic paralysis responds well to treatment. Treatment may prevent, and even reverse, progressive muscle weakness. Although muscle strength is initially normal between attacks, repeated attacks may eventually cause worsening and permanent muscle weakness between attacks.ComplicationsKidney stones(a side effect of acetazolamide)Heart arrhythmias during attacksDifficulty breathing, speaking, or swallowing during attacks (rare)Progressive muscle weaknessCalling your health care providerCall your health care provider if you have intermittent muscle weakness, particularly if there is a family history of periodic paralysis.Go to the emergency room or call the local emergency number (such as 911) if you faint or have difficulty breathing, speaking, or swallowing. These are emergency symptoms.PreventionHypokalemic periodic paralysis cannot be prevented. Because it can be inherited, genetic counseling may be advised for couples at risk for the disorder.Treatment prevents attacks of weakness. Before an attack, there may be leg stiffness or heaviness in the legs. Performing mild exercise when these symptoms start may help prevent a full-blown attack.ReferencesBarohn RJ. Muscle diseases. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 447.

How many alleles are typically present in a gene?

Typically, there are two alleles present in a gene, one inherited from each parent.

The total number of genes present in a population is the?

gene pool

Which type of gene or gene combination can be present in a generation without affecting phenotype?

A recessive gene or gene combination can be present in a generation without affecting the phenotype if it is masked by a dominant gene. This means that the trait associated with the recessive gene will only be expressed if an individual inherits two copies of the recessive gene.

A gene whose code is not expressed unless a similar allele is present is called an?

recessive gene