Unverricht-Lundborg disease (Baltic myoclonus)
Myoclonus epilepsy and ragged red fibres (MERRF syndrome)
Lafora disease
Neuronal ceroid lipofuscinoses
Sialidosis
Dentatorubropallidoluysian atrophy (DRPLA)
Noninfantile neuronopathic form of Gaucher disease
Tetrahydrobiopterin deficiencies
Alpers disease
Juvenile Huntington disease
Niemann-Pick disease type C
North Sea progressive myoclonus epilepsy (NSPME)

Unverricht-Lundborg disease
This disease manifests between six and sixteen years and is most prevalent in Scandinavia and the Baltic countries. Myoclonus gradually becomes worse and less susceptible to medication. Cognitive decline is slow and sometimes mild. Patients typically do not live beyond middle-age, but there are exceptions. Phenytoin, an old and commonly used anticonvulsant, is known to seriously exacerbate the condition. It has autosomal recessive inheritance, and is caused by a mutation in the cystatin B (EPM1) gene on chromosome 21q22.3, which was discovered in 1996. It has been described as the least severe type of PME. Myoclonus epilepsy and ragged red fibres (MERRF syndrome)
Onset of this disease may be at any time and the severity and progression are varied. Tonic-clonic seizures and dementia are less apparent than with other forms of PME. The cause is a mitochondrial DNA mutation, so most familial cases are transmitted from the mother. A skeletal muscle biopsy will show ragged red fibres, hence the name. Lafora body disease
This disease typically begins between six and nineteen years after apparently normal development and generally results in death within ten years. It is characterised by the presence of Lafora bodies (polyglucosan inclusions) in neurons and other body tissue. The generalized seizures are usually well controlled by anticonvulsants, but the myoclonus soon proves refractory to treatment.
Distal intestinal obstruction syndrome (DIOS) involves obstruction of the distal part of the small intestines by thickened intestinal content  and occurs in about 20% of mainly adult individuals with cystic fibrosis. DIOS was previously known as meconium ileus equivalent, a name which highlights its similarity to the intestinal obstruction seen in newborn infants with cystic fibrosis. DIOS tends to occur in older individuals with pancreatic insufficiency. Individuals with DIOS may be predisposed to bowel obstruction, though it is a separate entity than true constipation. Signs and symptoms
Signs and symptoms of DIOS include a sudden onset of crampy abdominal pain, vomiting, and a palpable mass (often in the right lower quadrant) in the abdomen. The characteristic abdominal pain is typically located in the center or right lower quadrant of the abdomen. X-rays of the abdomen may reveal stool in the colon and air-fluid levels in the small intestines. Diagnosis
A complete history and physical examination can be suggestive, especially if a palpable mass in the right lower quadrant of the abdomen is present (though this can be present in the absence of DIOS). Ultrasound and computed tomography (CT) imaging of the abdomen can confirm the diagnosis by demonstrating dilated loops of intestine with material in the intestinal lumen with bubbles. Air-fluid levels may be seen in those affected by DIOS. Classification
DIOS is sometimes classified by the degree of obstruction as incomplete or complete DIOS. Differential diagnosis
Additional diagnoses which may present with similar symptoms to DIOS include severe constipation, appendicitis, and intussusception.