When the gene is mutated, the eventually translated protein improperly folds its pore segment within the cell membrane because it has different amino acid chemistry, which renders the channel inactive. It is also possible for a mutation to reduce the number of channels produced by an individual, which leads to the development of Dravet syndrome.Currently, the SCN1A gene is the most clinically relevant; the largest number of epilepsy related mutations characterized thus far occur in this gene. Typically, a missense mutation in either the S5 or S6 segment of the sodium channel pore results in a loss of channel function and the development of Dravet syndrome. A heterozygous inheritance of an SCN1A mutation is all that is necessary to develop a defective sodium channel; patients with Dravet syndrome will still have one normal copy of the gene. Diagnosis
According to the Dravet Syndrome Foundation, the diagnostic criteria for DS requires the patient to present with several of the following symptoms:
Onset of seizures in the first year of life in an otherwise healthy infant
Initial seizures are typically prolonged and are generalized or unilateral
Presence of other seizure types (i.e.
Ainhum (from Portuguese, pronounced /aj.ˈɲũ/), also known as dactylolysis spontanea, is a painful constriction of the base of the fifth toe frequently followed by bilateral spontaneous autoamputation a few years later. Signs and symptoms
The groove begins on the lower and internal side of the base of the fifth toe, usually according to the plantar-digital fold. The groove becomes gradually deeper and more circular. The rate of spread is variable, and the disease may progress to a full circle in a few months, or still be incomplete after years. In about 75 percent of cases both feet are affected, though not usually to the same degree. There is no case reported where it begins in any other toe than the fifth, while there is occasionally a groove on the fourth or third toe. The distal part of the toe swells and appears like a small potato. The swelling is due to lymphatic edema distal to the constriction. After a time crusts can appear in the groove which can be infected with staphylococcus. While the groove becomes deeper, compression of tendons, vessels and nerves occurs. Bone is absorbed by pressure, without any evidence of infection. After a certain time all structures distal the stricture are reduced to an avascular cord. The toe’s connection to the foot becomes increasingly slender, and if it is not amputated, it spontaneously drops off without any bleeding. Normally it takes about five years for an autoamputation to occur. Cole describes four stages of ainhum:

Pain is present in about 78% of cases.