DRPLA

Excerpt

Clinical characteristics: Dentatorubral-pallidoluysian atrophy (DRPLA) is a progressive disorder of ataxia, myoclonus, epilepsy, and progressive intellectual deterioration in children and ataxia, choreoathetosis, and dementia or character changes in adults. Onset ranges from before age one year to age 72 years; mean age of onset is 31.5 years. The clinical presentation varies depending on the age of onset. The cardinal features in adults are ataxia, choreoathetosis, and dementia. Cardinal features in children are progressive intellectual deterioration, behavioral changes, myoclonus, and epilepsy.

Diagnosis/testing: The diagnosis of DRPLA is established in a proband with suggestive clinical findings and a family history of DRPLA or by the identification of a heterozygous pathogenic CAG trinucleotide expansion in ATN1 by molecular genetic testing. The CAG repeat length in individuals with DRPLA ranges from 48 to 93.

Management: Treatment of manifestations: Standard anti-seizure medication for seizures; appropriate psychotropic medications for psychiatric manifestations; symptomatic treatment of ataxia with riluzole and rehabilitation therapy; adaptation of environment and care to the level of dementia; appropriate educational programs for children.

Agents/circumstances to avoid. General anesthesia can increase the risk of intra- and postoperative seizures.

Pregnancy management. The use of anti-seizure medication during pregnancy may have an effect on the fetus. Discussion of the risks and benefits of using a given anti-seizure medication during pregnancy should ideally take place prior to conception; transition to a lower-risk medication may be possible. The use of riluzole during pregnancy has not been well studied in humans.

Genetic counseling: DRPLA is inherited in an autosomal dominant manner. The risk to the offspring of an affected individual of inheriting an expanded CAG repeat is 50%. The size of the repeat transmitted to the offspring depends on the size of the parent's repeat and the sex of the transmitting parent. Prenatal testing for a pregnancy at increased risk is possible using molecular genetic testing if the diagnosis in the family has been confirmed.