But in either form of myotonia congenita, the terms strictest sense reflects that the disease is genetically present from birth, although the clinical onset may be delayed.With the advent of genetic testing, it has recently been found that some typically recessive mutations may occur in a dominant fashion in some individuals. The reason for this is not known.Because several CLCN1 mutations can cause either Becker disease or Thomsen disease, doctors usually rely on characteristic signs and symptoms to distinguish the two forms of myotonia congenita. However, myotonia caused by CLCN1 mutations can occasionally be clinically indistinguishable from myotonia caused by sodium channel mutations (SCN4A mutations) resulting in the similar disease paramyotonia congenita.A so-called Finnish heritage disease, congenital myotonia is more common in Finland and among ethnic Finns. A molecular study of the CLCN1 gene in 24 families in northern Finland, including 46 affected individuals, showed that although the inheritance appeared to be dominant (Thomsen type), in fact it is recessive (Becker type). Differential diagnosis
Sodium channel myotonias (SCN4A)

Potassium-aggravated myotonia (acetazolamide responsive myotonia)
Paramyotonia congenita
Hyperkalemic periodic paralysisDystrophies

Myotonic dystrophy (myotonic muscular dystrophy: Type 1 and Type 2)Potassium channel disorders (KCNJ2)

Andersen-Tawil syndromeOther disorders

Thyroid disorders
Neuromyotonia (Isaacs Syndrome)
Schwartz–Jampel syndrome
Stiff person syndrome
Brody myopathy (Brody Disease, Brodys Disease, Brodys Myopathy)

Treatment
Some cases of myotonia congenita do not require treatment, or it is determined that the risks of the medication outweigh the benefits. If necessary, however, symptoms of the disorder may be relieved with quinine, ranolazine, procainamide, flecainide, phenytoin, carbamazepine, mexiletine and other anticonvulsant drugs.
A myxoma (New Latin from Greek muxa for mucus) is a myxoid tumor of primitive connective tissue. It is most commonly found in the heart (and is the most common primary tumor of the heart in adults) but can also occur in other locations. Types
Table below:
1.^ SMA, smooth muscle actin. 2.^ MSA, muscle-specific actin. 3.^ EMA, epithelial membrane antigen. Symptoms and signs
Symptoms associated with cardiac myxomas are typically due to the effect of the mass of the tumor obstructing the normal flow of blood within the chambers of the heart. Because pedunculated myxomas are somewhat mobile, symptoms may only occur when the patient is in a particular position. Some symptoms of myxoma may be associated with the release of interleukin 6 (IL-6) by the myxoma. High levels of IL-6 may be associated with a higher risk of embolism of the myxoma.Symptoms of a cardiac myxoma include:
Dyspnea on exertion
Paroxysmal nocturnal dyspnea
Fever
Weight loss (see cachexia)
Lightheadedness or syncope (Loss of consciousness)
Hemoptysis
Sudden death
Tachycardia or milder heartrate, i.e. 75 - 100 cycl/min

Location
Ocular myxoma
Myxoma is a rare, benign stromal tumor of mesenchymal origin often confused with other conjunctival stromal tumors. Conjunctival myxomas are thought to originate in Tenons capsule and can masquerade as conjunctival lymphoma, lymphangioma, ocular surface squamous neoplasia (OSSN), or amelanotic melanoma. Atrial myxoma
Cutaneous myxoma
Odontogenic myxoma

Atrial myxoma
Myxomas are usually located in either the left or right atrium of the heart; about 86 percent occur in the left atrium.Myxomas are typically pedunculated, with a stalk that is attached to the interatrial septum.