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1/87. prenatal diagnosis of fatal infantile olivopontocerebellar hypoplasia syndrome.

    We report the first case of prenatal diagnosis of fatal infantile olivopontocerebellar hypoplasia syndrome, OMIM 225753. Ultrasound findings noted at 28 weeks' gestation included polyhydramnios, a small stomach bubble, a small but morphologically normal cerebellum, dilatation of the fourth ventricle, and long periods of normal fetal movement punctuated by sudden bursts of violent seizure-like activity of the fetal extremities. At birth, the child was noted to be hypertonic, myoclonic, hyper-reflexic, demonstrated poor gastrointestinal motility, and had severe apneic episodes. magnetic resonance imaging (MRI) demonstrated marked hypoplasia or atrophy of the cerebellum, pons and medulla, mild atrophy of the cerebral cortex, and mild ex vacuo venticulomegaly of the fourth, third and lateral ventricles. This child died from respiratory insufficiency at 14 days of age. The parents of this child had previously lost a child with similar clinical and anatomical findings. Prenatal sonographers should be aware of the existence of this rare syndrome and should look carefully at the size of the cerebellum in cases of polyhydramnios or when in utero 'seizure-like' activity is seen. The importance of establishing this diagnosis lies in the fact that it appears to have a very poor postnatal prognosis and is likely to be inherited as an autosomal recessive disease. ( info)

2/87. Genetic factors in human sleep disorders with special reference to Norrie disease, prader-willi syndrome and Moebius syndrome.

    Sleep-wake problems are common in specific inborn errors of metabolism and structure of the central nervous system. Psychological factors, behavioural difficulties, metabolic disturbances, and widespread rather than focal damage to the nervous system are present in many of these diseases and all influence the sleep-wake cycle. However, a number of conditions cause relatively focal damage to the neuroanatomical substrate of sleeping and waking. These include fatal familial insomnia, with involvement of the prion protein gene on chromosome 20, Norrie disease, the prader-willi syndrome and the Moebius syndrome. The last three important conditions, although rare, are considered in detail in this review. They result in sensory deprivation, hypothalamic and mid-brain damage, and involve the X-chromosome, chromosome 15, and chromosome 13, respectively. These conditions cause a wide variety of sleep disturbance, including parasomnias, daytime sleepiness, and a condition like cataplexy. The place of the relevant gene products in normal sleep regulation needs further exploration. ( info)

3/87. Pontocerebellar hypoplasia associated with respiratory-chain defects.

    Pontocerebellar hypoplasias are congenital disorders of brain morphogenesis which include such diverse etiologies as carbohydrate-deficient glycoprotein syndrome type 1, cerebromuscular dystrophies (walker-warburg syndrome, Fukuyama syndrome, muscle-eye-brain disease) and at least two types of autosomal recessive neurodegenerations known as pontocerebellar hypoplasia type I and II. Pontocerebellar hypoplasia type 1 is a lethal phenotype and clinical features include congenital contractures, respiratory insufficiency, central and peripheral motor dysfunction and spinal anterior horn degeneration. Type 2 is characterized by progressive microcephaly, extrapyramidal dyskinesia and normal spinal cord findings. In this paper, we describe a girl, born at 33 weeks of gestation, presenting with respiratory insufficiency and multiple contractures. MRI scan of the brain demonstrated pontocerebellar hypoplasia and cortical and diffuse periventricular white matter abnormalities. Postmortem examination showed pontocerebellar hypoplasia with extensive gliosis of the periventricular white matter and of the basal ganglia with normal spinal cord findings. histology of skeletal muscle was normal. Biochemical analysis demonstrated multiple deficiencies of respiratory chain enzymes in skin fibroblasts. This case demonstrates a lethal phenotype of pontocerebellar hypoplasia without spinal cord abnormalities associated with a respiratory-chain disorder. The diagnostic workup in a patient whose brain image shows pontocerebellar hypoplasia should include a search for respiratory-chain impairment. ( info)

4/87. A case of spinocerebellar ataxia type 6 mimicking olivopontocerebellar atrophy.

    Spinocerebellar ataxia type 6 (SCA6) is an autosomal dominant, slowly progressive cerebellar ataxia without multisystem involvement. We report a 57-year-old woman with genetically confirmed SCA6 who showed clinical features of olivopontocerebellar atrophy. Conventional T2-weighted and FLAIR MRI demonstrated high signal in the middle cerebellar peduncles, in addition to mild atrophy of the pons and cerebellum. ( info)

5/87. A case of nocturnal polyuria in olivopontocerebellar atrophy.

    We report a case of olivopontocerebellar atrophy without sleep apnea syndrome who presented nocturnal polyuria. It is considered that a disturbance in the circadian rhythm for arginine vasopressin secretion due to degeneration of suprachiasmatic nuclei and marked increase in the secretion of atrial natriuretic peptide due to abnormal diurnal variation in blood pressure may be involved in the mechanism of nocturnal polyuria. ( info)

6/87. Disappearance of rhythmic involuntary movements during sleep in a case of olivopontocerebellar atrophy.

    We report on a 54-year-old woman with an 8 or so year history of olivopontocerebellar atrophy associated with the rhythmic involuntary movements of the left upper and lower limbs, and cervical region. Surface electromyogram of the left upper limb revealed rhythmicity (about 3 Hz) and reciprocity between antagonistic muscles, which disappeared on polysomnography at all sleep stages including rapid eye movement sleep without atonia. These were characterized by the co-existence of rhythmic skeletal myoclonus and parkinsonian tremor. These findings suggest that a disturbance of the striatonigral system as well as the dentato-rubro-olivary circuit may be involved in these movements. It also seems that their fate is dependent on the level of wakefulness and that the ascending reticular activating system also plays a role in the development of these movements. ( info)

7/87. Familial pontocerebellar hypoplasia type I with anterior horn cell disease.

    We report the association of pontocerebellar hypoplasia and anterior horn cell disease in three female siblings. One child presented with the classical clinical and neuropathological features of pontocerebellar hypoplasia with associated anterior horn cell disease, described by Barth as pontocerebellar hypoplasia type I. This patient showed polyhydramnios, congenital contractures, respiratory insufficiency, hypotonia, areflexia, listlessness and myoclonic seizures. Postmortem examination revealed a loss of neurons and reactive gliosis in the pontocerebellum and in addition anterior horn cell atrophy resembling Werdnig-Hoffmann disease. Another sibling demonstrated the same clinical symptoms. However neuropathological findings showed evidence for pontocerebellar hypoplasia only. The third sibling was examined after induced fetal abortion because of prenatally diagnosed arthrogryposis. Anterior horn cell disease was obvious histologically whereas pontocerebellar hypoplasia could not be demonstrated due to cerebral autolysis. The similar clinical and neuropathological findings in the three reported siblings suggest a common genetic defect with different patterns of pontocerebellar hypoplasia and associated anterior horn cell disease. The gene defect of this rare disorder is still unknown. The 'survival motor neuron' gene of spinal muscular atrophy was not found in these three siblings. ( info)

8/87. Olivopontocerebellar atrophy: paraneoplastic syndrome of brain tumour?

    We describe a patient who, three years after the onset of an olivopontocerebellar atrophy, developed a right cerebral tumour. The cerebellar symptomatology also included, as in other cerebellar patients previously described, a peripheral dysgraphia. Because this deficit of writing is generally reported in patients with right cerebral lesion, the authors hypothesized that functional alterations of supratentorial structures preceding the tumour by years may be able to damage the neural substrates connecting cerebral and cerebellar structures and to produce cerebellar atrophy. ( info)

9/87. fatal outcome in a case of pontocerebellar hypoplasia type 2.

    Pontocerebellar hypoplasia (PCH) is a very rare congenital (autosomal recessive) condition with fetal onset. Only a few cases have been published on the basis of both clinical data (symptoms/neuroradiological imaging) and autopsy results. This paper reports on such a case involving a 1.5-year-old male infant. The child suffered from severe psychomotor delay, extrapyramidal dyskinesia and epileptic seizures, but did not exhibit signs of spinal muscular atrophy as related to PCH type 1. magnetic resonance imaging (MRI) at the age of 6 months demonstrated olivo-pontine and bilateral cerebellar hypoplasia. The boy was unexpectedly found dead. autopsy disclosed a severe aspiration of gastric contents as the final cause of death. The neuropathological examination confirmed PCH type 2 (according to Barth [brain Dev., 15 (1993) 411-422]) with marked microcephaly and olivopontocerebellar hypoplasia. Histologically, decreased density of olivo-pontine neurons, reduction of granular and Purkinje's cell layers of the cerebellum, slight astroglial proliferation and fragmented appearance of the dentate nuclei were observed. The immunohistochemical expression pattern was determined using antibodies against glial fibrillary acidic protein, synaptophysin and neurofilament protein. Summarizing, typical features of PCH type 2 were present and proved by clinical course, MRI and autopsy. Despite severe symptoms due to a natural disease this rare neurogenetic entity can become of forensic interest, when sudden unexpected death occurs. ( info)

10/87. Pontocerebellar hypoplasia in two siblings with dysmorphic features.

    We present two siblings with pontocerebellar hypoplasia who have progressive microcephaly, mental and motor retardation, truncal ataxia, strabismus, and progressive spasticity and hyperreflexia of the lower limbs. Extrapyramidal dyskinesia and epilepsy, other main clinical features of pontocerebellar hypoplasia, are absent. The older sibling also has a high arched palate, triangular-shaped face, thoracolumbar scoliosis, pectus carinatum, kyphosis, cubitus valgus, arachnodactyly, long extremities, and a tall stature, which were not previously reported in association with pontocerebellar hypoplasia. The clinical phenotype should be expanded, especially within type II, with the reports of additional cases. ( info)
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