Infantile convulsions and paroxysmal choreoathetosis in a consanguineous family

Infantile convulsions and paroxysmal choreoathetosis is a rare autosomal-dominant disorder characterized by variable presentation of benign infantile seizures and paroxysmal dyskinesia. The disease gene was mapped to chromosome 16p12-q12. We report a consanguineous Turkish family with three individuals affected by infantile convulsions and paroxysmal choreoathetosis. Two siblings whose parents were first cousins had benign infantile convulsions and paroxysmal choreoathetosis. Whereas their father presented only paroxysmal choreoathetosis. The siblings displayed an earlier age of onset and increased frequency of the paroxysmal symptoms than their father. We genotyped the pedigree with polymorphic microsatellite markers, spanning the pericentromeric region of chromosome 16. Construction of the haplotypes demonstrated the segregation of the disease with the infantile convulsions and paroxysmal choreoathetosis locus. The disease was inherited as an autosomal-dominant trait with incomplete penetrance. The affected father was heterozygous for the disease haplotype. However, the two affected siblings manifested homozygosity for the disease haplotype. By haplotype analysis, we confirmed the assignment of the locus for infantile convulsions and paroxysmal choreoathetosis to chromosome 16p12-q12 in this family, and our results also demonstrate that homozygotes for infantile convulsions and paroxysmal choreoathetosis may have a more severe form of the disease than heterozygotes. Demir E, Prud'homme JF, Topcu M. Infantile convulsions and paroxysmal choreoathetosis in a consanguineous family.     

Typical and Atypical Forms of Paroxysmal Choreoathetosis

Two children with clinical pictures of paroxysmal kinesinogenic choreoathetosis and paroxysmal dystonic choreoathetosis are described and compared with previous reports with regard to diagnostic procedures, therapeutic approach and prognosis. A third case, characterized by paroxysmal dyskinesia induced by exercise and associated with choreiform nonprogressive signs, is also described. Such an association has not been reported previously. This unusual clinical picture indicates the possibility of intermediate forms in the paroxysmal choreoathetosis group and suggests a relationship between paroxysmal motor disorders and benign familial chorea with early onset.     

Paroxysmal dyskinesis and epilepsy

Based on the available literature, we outline the classification criteria of paroxysmal involuntary movements with instant onset and termination. Four types of those movements are currently distinguished: dystonic Mount-Reback paroxysmal choreoathetosis, kinesigenic paroxysmal choreoathetosis, exercise-induced paroxysmal dystonia, and hypnogenic paroxysmal dystonia. We present the clinical characteristics of those entities, as well as diagnostic and therapeutic aspects. An association with epilepsy is emphasised, which seems to predominantly apply to hypnogenic dystonia and kinesigenic paroxysmal choreoathetosis.     

Phenytoin-induced choreoathetosis in patients with severe myoclonic epilepsy in infancy.

We describe three patients with severe myoclonic epilepsy in infancy (SME) who suffer from choreoathetosis due to the adverse effect of phenytoin. Choreoathetosis appeared when these patients were 8, 19, and 21 years old, 2 days to 6 months after increasing the phenytoin dosage. Choreoathetosis disappeared when the phenytoin dosage was decreased. The two elder patients experienced episodic and rather paroxysmal onset of long-lasting choreoathetosis, requiring the differential diagnosis from degenerative disease. In one of the patients, an ictal SPECT revealed decreased perfusion in the basal ganglia contralateral to the unilateral choreoathetosis. Polypharmacy, including carbamazepine and zonisamide, may have facilitated the onset of choreoathetosis. Phenytoin-induced choreoathetosis in the patients with SME is an important differential diagnosis among degenerative disorders involving involuntary movements. The episodic and paroxysmal nature of this movement disorder can delay its diagnosis and effective treatment. Patients with SME appear to be particularly vulnerable to this side effect of phenytoin, indicating the possible involvement of basal ganglia in the pathophysiology of this type of epilepsy.     

Benign familial infantile seizures: further delineation of the syndrome

Benign familial infantile seizures are an autosomal dominant epilepsy disorder that is characterized by convulsions, with onset at age 3 to 12 months and a favorable outcome. Benign familial infantile seizures have been linked to chromosome 19q whereas infantile convulsions and choreoathetosis syndrome, in which benign familial infantile seizure is associated with paroxysmal choreoathetosis, has been linked to chromosome 16p 12-q12. Many additional families from diverse ethnic backgrounds have similar syndromes that have been linked to the chromosome 16 infantile convulsions and choreoathetosis syndrome region. Moreover, in one large pedigree with paroxysmal kinesiogenic dyskinesias only, the syndrome has also been linked to the same genomic area. Families with pure benign familial infantile seizures may be linked to chromosome 16 as well. In this study, we present a series of 19 families and 24 otherwise healthy infants with benign familial infantile seizures. Two of these families include members affected with benign familial infantile seizures and paroxysmal choreoathetosis. We included patients with normal neurologic examinations, who started having simple partial seizures, complex partial seizures, or apparently generalized seizures without recognized etiology between 2 months and 2 years of age. Neurologic studies were normal, but in all patients, there was a history of similar seizures and age at onset in either the father or the mother. Twenty-four patients (14 girls and 10 boys) were evaluated at our hospital between February 1990 and February 2001. Age at onset, sex, family history of epilepsy and/or paroxysmal dyskinesias, neurologic examination, semiology, distribution, and frequency and duration of seizures were evaluated. Electroencephalographic (EEG) and neuroradiologic studies were also performed. Seizures began between 3 and 22 months of life, with a median age of 5 1/2 months. Nine patients (37.5%) had only apparently generalized seizures, 5 patients (20.8%) had only partial seizures, and 10 patients had both partial and apparently generalized seizures (41.6%). Seizures were invariably brief, occurred during the waking state (100%), and presented mainly in clusters in 12 patients (50%). Interictal EEG was normal in 23 patients (95.8%). Sixteen patients (66.6%) had a confirmed history of convulsions in family members other than parents. Twenty-two patients became seizure free after 30 months of life. Two brothers in the same family had brief paroxysmal episodes of choreoathetosis in the hemibody triggered by stress while awake at 15 and 17 years old, respectively. One of them had paroxysmal choreoathetosis only, and the other was associated with benign familial infantile seizures. One father had brief spontaneous episodes of paroxysmal choreoathetosis when awake at age 18 years. All of them had a good response to antiepilepsy drugs, and neurologic examination and EEG and neuroradiologic studies were normal. Benign familial infantile seizure is a genetic epilepsy syndrome with autosomal dominant inheritance. It may be associated with paroxysmal choreoathetosis (infantile convulsions and choreoathetosis syndrome), which has been linked to the chromosome 16 infantile convulsions and choreoathetosis syndrome region. Patients in families with infantile convulsions and choreoathetosis syndrome could display either benign familial infantile seizures or paroxysmal choreoathetosis or both. It is likely that the disease in families with pure benign familial infantile seizures may be linked to the infantile convulsions and choreoathetosis region as well. We cannot exclude the possibility that the youngest patients may develop choreoathetosis or other dyskinesias later in life.     

Paroxysmal choreoathetosis associated with thyrotosicosis

Acquired paroxysmal choreoathetosis can be associated with a variety of structural and metabolic disorders. A patient is presented who had paroxysmal choreoathetosis associated with thyrotoxicosis and who responded to treatment of the underlying thyroid disease.     

Familial paroxysmal dystonic choreoathetosis and its differentiation from related syndromes

Four generations of a family are described in which 7 of 8 affected members suffered from prolonged dystonic seizures; the eighth member's attacks were those of paroxysmal choreoathetosis. The attacks lasted up to 4 hours, were precipitated by alcohol, emotion, or fatigue, and responded poorly to phenytoin and barbiturates but were controlled by clonazepam. Autopsy on an affected child who died a "crib death" at the age of 2 years disclosed no major abnormality of the brain. This family appears to have the same condition as that described by Mount and Reback in 1940, Forssman in 1961, and Richards and Barnett in 1968, which the last authors termed paroxysmal dystonic choreoathetosis to distinguish it from the more common movement-induced (kinesigenic) form of the disorder. Analysis of reports of 100 cases of paroxysmal kinesigenic choreoathetosis shows that the attacks last less than 5 minutes, are precipitated by sudden movement or startle, and usually respond well to phenytoin or barbiturates. A clinical classification is presented in which the kinesigenic form is divided into a familial group (72% of cases) and a sporadic group (28% of cases) and contrasted with paroxysmal dystonic choreoathetosis. One family with an intermediate form, in which dystonic choreoathetosis was provoked by continued exertion and lasted for up to 30 minutes, is also reported.     

Ten Year Follow-up of Paroxysmal Choreoathetosis: A Sporadic Case Becomes Familial

A 30-year-old woman is reported who was originally described in 1967 as an isolated instance of paroxysmal choreoathetosis. In the subsequent 10 years, her movement disorder has decreased in severity. However, she now has a 7-year-old daughter with a similar but more persistent and more serious condition. This family emphasizes both variability of manifestations of paroxysmal choreoathetosis and the importance of genetic factors.     

Effective treatment with oxcarbazepine in paroxysmal kinesigenic choreoathetosis

Paroxysmal kinesigenic choreoathetosis is often responsive to anticonvulsants such as carbamazepine and phenytoin. We report a boy with paroxysmal kinesigenic choreoathetosis, which is dramatically relieved by oxcarbazepine even after unsatisfactory treatment with carbamazepine and other medications.     

Autosomal dominant paroxysmal kinesigenic choreoathetosis: An electroneurophysiological study

A case of an 11-year-old boy with an autosomal dominant form of paroxysmal kinesigenic choreoathetosis is presented. Routine EEG, sleep EEG recording, and registration of visual evoked potentials and somatosensory evoked potentials were normal. EEG with videomonitoring and registration of event-related potentials, however, showed abnormalities, which are discussed in detail. Our data provide further arguments in support of the hypothesis that paroxysmal kinesigenic choreoathetosis is the expression of a dysbalance in the cortico-striopallidal-thalamic loop, and has an extrapyramidal genesis.     

Familial dystonic choreoathetosis with myokymia; a sleep responsive disorder.

A family is presented with paroxysmal dystonic choreoathetosis transmitted as a dominant trait over five generations. The family is unusual in the marked responsiveness of the episodes to short periods of sleep in several members, in the very variable age of onset, and in the association with prominent myokymia in some cases. These overlap features suggest a link between paroxysmal dystonic choreoathetosis and familial paroxysmal ataxia with myokymia.     

Focal paroxysmal kinesigenic choreoathetosis

Three cases of paroxysmal kinesigenic choreoathetosis are described in whom unilateral attacks were focally induced, together with a case in whom bilateral attacks only occured. Treatment with phenytoin was effective in all cases. The aspects of the literature relating to focal and generalised attacks in paroxysmal kinesigenic choreoathetosis are reviewed.     

Short report: Paroxysmal choreoathetosis as a presenting symptom in idiopathic hypoparathyroidism

A patient with idiopathic hypoparathyroidism presenting with spells of paroxysmal choreoathetosis is described. The possible mechanisms by which hypoparathyroidism induces choreoathetosis and other extrapyramidal motor dyfunctions are discussed. The need for screening patients with extrapyramidal disease for hypoparathyroidism is stressed.     

New family with paroxysmal exercise-induced dystonia and epilepsy.

To date, there are few reports of paroxysmal exercise-induced dystonia associated with familial epilepsy. We describe a family with 4 affected members spanning 3 generations, suggestive of autosomal-dominant inheritance, who exhibited typical exercise-induced dystonia, different types of epilepsy (absence and primary generalized seizures), developmental delay, and migraine in variable combinations. Linkage of the disease to loci on chromosome 2 (paroxysmal nonkinesigenic dyskinesia) and chromosome 16 (paroxysmal kinesigenic choreoathetosis, infantile convulsions with choreoathetosis) was excluded, suggesting an as yet unidentified underlying genetic basis.     

Therapeutic aspects of kinesiogenic paroxysmal choreoathetosis and familial paroxysmal choreoathetosis of the Mount and Reback type

Six generations of a family with paroxysmal choreoathetosis of the Mount and Reback type were studied. Neurological investigation and follow-up of the symptoms were possible for four generations, in which 15 members suffered from the disease. The attacks could be provoked by alcohol and intensified by caffeine or emotional excitement. Phenytoin, primidone and carbamazepine had no therapeutic effect. Treatment with L-dopa could provoke the choreoathetosis. Haloperidol was the most effective treatment and valproic acid was also able to reduce drastically the frequency and intensity of the attacks. Three patients with sporadic kinesiogenic, paroxysmal choreoathetosis were also studied, whose choreoathetosis was induced by movement. Treatment with carbamazepine or phenytoin was effective, but haloperidol increased the severity of the choreoathetoid attacks.     

Co-segregation of benign infantile convulsions and paroxysmal kinesigenic choreoathetosis

We report seven families and two sporadic cases in which benign infantile convulsions and paroxysmal kinesigenic choreoathetosis were co-segregated. Clinical investigations included physical and neurological examinations, blood electrolyte values, interictal and ictal electroencephalograms, and computed tomography or magnetic resonance imaging of the brain. The family pedigree was confirmed and the clinical history of the relatives was obtained. Seventeen individuals developed infantile convulsions followed by paroxysmal dyskinesias during childhood or adolescence. Six had only infantile convulsions, and two had only paroxysmal dyskinesias. The seizures never persisted into childhood or recurred in adulthood. The seizure type was a complex partial seizure, with or without secondary generalization, in nine of 14 patients. Paroxysmal dyskinesias, a subgroup of paroxysmal kinesigenic choreoathetosis, occurred for less than 5 min. The attacks of dyskinesias began at age 5-12 years in most patients, and tended to remit in adulthood. The mode of inheritance was apparently autosomal dominant in four of the families (17 affected individuals), who were diagnosed with ICCA syndrome (infantile convulsions and paroxysmal choreoathetosis). However, the condition occurred only among siblings in three families (six patients), and sporadically in two patients, suggesting genetic heterogeneity in this distinct co-segregation.     

Multicenter study of paroxysmal dyskinesias in Japan--clinical and pedigree analysis.

To investigate the clinical features of paroxysmal dyskinesias and carry out a pedigree analysis, we conducted a multicenter survey in Japan. A questionnaire was mailed to 229 medical institutions. A total of 150 patients with paroxysmal kinesigenic choreoathetosis (PKC), including 53 sporadic cases and 97 affected individuals from 32 pedigrees, were identified. The mean age of onset of PKC was 8.8 years, and 80% of the cases were men. Of the 32 pedigrees with familial occurrence, 18 (56%) were compatible with an autosomal-dominant inheritance (AD) with complete penetrance, and seven (22%) had AD with incomplete penetrance; the remaining seven were sibling recurrence cases with apparently healthy parents. In six of seven familial cases with incomplete penetrance, the disease gene was thought to be transmitted by clinically unaffected females. Paroxysmal dystonic choreoathetosis (PDC) was found in five cases, including two sporadic cases and three affected individuals from two pedigrees; the mean age of onset was 0.6 years, and a male predominance was noted (male:female = 4:1). There was one case of paroxysmal hypnogenic dyskinesia and one case of paroxysmal exertion-induced dyskinesia. There is an unexplained male predominance for paroxysmal dyskinesias. When the genetic defect of patients with paroxysmal dyskinesias is identified, the pathophysiology of the disease will become more clear.     

Paroxysmal dyskinesias as a paradigm of paroxysmal movement disorders

Paroxysmal dyskinesias are genetically and clinically heterogeneous. Paroxysmal kinesigenic choreoathetosis is frequently familial, with autosomal-dominant transmission. Benign infantile convulsions can be observed in these families and both diseases as linked to the pericentromeric region of chromosome 16. Two different forms of paroxysmal dystonic choreoathetosis are distinguished on clinical grounds, by the presence or absence of spasticity, and genetically, as they are linked with loci on different chromosomes. Among the paroxysmal disorders, these diseases may belong to the group of channelopathies.     

Paroxysmal dystonic head tremor

Two patients with paroxysmal attacks of "no-no" direction head tremor and mild torticollis are described. One of them had the characteristic features of paroxysmal dystonic choreoathetosis and responded well to clonazepam.     

Paroxysmal kinesigenic dystonic choreoathetosis associated with a thalamic infarct

We describe a patient with the development of paroxysmal kinesigenic dystonic choreoathetosis (PKDC) after a thalamic infarct. PKDC consists of brief episodes of dystonia or choreoathetosis triggered by movement. PKDC improves with anticonvulsants, and in some cases, with L-Dopa or anticholinergics. We review PKDC, and relate its salient features to idiopathic and secondary torsion dystonia. We postulate a similar underlying pathophysiology.