Guideline for the diagnosis and management of glutaryl-CoA dehydrogenase deficiency (glutaric aciduria type I).

Glutaryl-CoA dehydrogenase (GCDH) deficiency is an autosomal recessive disease with an estimated overall prevalence of 1 in 100 000 newborns. Biochemically, the disease is characterized by accumulation of glutaric acid, 3-hydroxyglutaric acid, glutaconic acid, and glutarylcarnitine, which can be detected by gas chromatography-mass spectrometry of organic acids or tandem mass spectrometry of acylcarnitines. Clinically, the disease course is usually determined by acute encephalopathic crises precipitated by infectious diseases, immunizations, and surgery during infancy or childhood. The characteristic neurological sequel is acute striatal injury and, subsequently, dystonia. During the last three decades attempts have been made to establish and optimize therapy for GCDH deficiency. Maintenance treatment consisting of a diet combined with oral supplementation of L: -carnitine, and an intensified emergency treatment during acute episodes of intercurrent illness have been applied to the majority of patients. This treatment strategy has significantly reduced the frequency of acute encephalopathic crises in early-diagnosed patients. Therefore, GCDH deficiency is now considered to be a treatable condition. However, significant differences exist in the diagnostic procedure and management of affected patients so that there is a wide variation of the outcome, in particular of pre-symptomatically diagnosed patients. At this time of rapid expansion of neonatal screening for GCDH deficiency, the major aim of this guideline is to re-assess the common practice and to formulate recommendations for diagnosis and management of GCDH deficiency based on the best available evidence.

Detection of chromosomal imbalances in children with idiopathic mental retardation by array based comparative genomic hybridisation (array-CGH).

Chromosomal aberrations are a common cause of multiple anomaly syndromes that include growth and developmental delay and dysmorphism. Novel high resolution, whole genome technologies, such as array based comparative genomic hybridisation (array-CGH), improve the detection rate of submicroscopic chromosomal abnormalities allowing re-investigation of cases where conventional cytogenetic techniques, Spectral karyotyping (SKY), and FISH failed to detect abnormalities. We performed a high resolution genome-wide screening for submicroscopic chromosomal rearrangements using array-CGH on 41 children with idiopathic mental retardation (MR) and dysmorphic features. The commercially available microarray from Spectral Genomics contained 2600 BAC clones spaced at approximately 1 Mb intervals across the genome. Standard chromosome analysis (>450 bands per haploid genome) revealed no chromosomal rearrangements. In addition, multi-subtelomeric FISH screening in 30 cases and SKY in 11 patients did not detect any abnormality. Using array-CGH we detected chromosomal imbalances in four patients (9.8%) ranging in size from 2 to 14 Mb. Large scale copy number variations were frequently observed. Array-CGH has become an important tool for the detection of chromosome aberrations and has the potential to identify genes involved in developmental delay and dysmorphism. Moreover, the detection of genomic imbalances of clinical significance will increase knowledge of the human genome by performing genotype-phenotype correlation.

Myosin heavy chain IIa gene mutation E706K is pathogenic and its expression increases with age.

BACKGROUND: The authors recently described a new autosomal dominant myopathy (OMIM 605637 inclusion body myopathy 3) associated with a missense mutation in the myosin heavy chain (MyHC) IIa gene (MyHC IIa, Human Gene Map [HGM] locus MYH2). Young patients showed minor changes in their muscle biopsies, although dystrophic alterations and rimmed vacuoles with 15- to 20-nm tubulofilaments identical to those in sporadic inclusion body myositis (s-IBM) were observed in some of the adult (especially older) patients. The current study was undertaken to investigate the relation between expression of the mutant MyHC IIa and pathologic changes in muscle. METHODS: The expression of MyHC IIa in nine muscle specimens from six individuals carrying the mutation was analyzed by immunohistochemistry, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and a new reverse transcriptase--PCR method to measure the relative abundance of the various MyHC transcripts. RESULTS: Young patients with muscle weakness and minor pathologic changes in muscle expressed MyHC IIa at undetectable levels. MyHC IIa was expressed at high levels in adults with a progressive clinical course and dystrophic muscle changes. In these cases, a large number of muscle fibers were hybrids with expression of more than one MyHC isoform. Both MyHC IIa alleles were equally expressed. The relative level of MyHC IIa transcripts exceeded that of the corresponding protein, indicating an increased turnover of mutated protein. MyHC IIa expression was a consistent finding in muscle fibers with rimmed vacuoles. CONCLUSIONS: The clear correlation between pathologic changes and expression of MyHC IIa indicates that defects in MyHC may lead not only to muscle weakness but also to muscle degeneration. The consistent expression of MyHC IIa in muscle fibers with rimmed vacuoles indicates that the breakdown of sarcomeric proteins is a key element in the pathogenesis of rimmed vacuoles of s-IBM type.

Linkage studies in progressive myoclonus epilepsy: Unverricht-Lundborg and Lafora's diseases.

The progressive myoclonus epilepsies (PME) are a heterogeneous group of rare genetic disorders. Unverricht-Lundborg disease and Lafora's disease are two major classic forms of PME. We recently assigned the gene for Unverricht-Lundborg disease (EPM1) to human chromosome 21 band q22.3. We have now refined the localization of EPM1 by linkage analysis between the disease phenotype and nine DNA markers in 13 Finnish families. Loci MX1 and CD18 flank the EPM1 interval, which spans a distance of about 3.5 megabases. In this 20-centimorgan interval, no recombinations were detected between EPM1 and marker loci BCEI, D21S19, D21S42, D21S113, D21S154, and PFKL. Within this interval a maximum multipoint lod score of 11.04 was reached at loci D21S154-PFKL. In two Swedish families with Unverricht-Lundborg disease no recombinations were detected. In three Italian families with Lafora's disease the linkage results suggested that EPM1 is not the locus for Lafora's disease.

Follow-up of nemaline myopathy in two patients with novel mutations in the skeletal muscle alpha-actin gene (ACTA1).

Nemaline myopathy has been associated with mutations in five different genes, which all encode protein components of the sarcomeric thin filaments. We report follow-up studies in two children with mutations not previously described in skeletal muscle alpha-actin (ACTA1). Case 1 was a male patient who after birth suffered from pronounced muscle weakness and hypotonia. Muscle biopsy showed small fibers with numerous rods. He failed to achieve any motor milestones. At the age of 17 he required 24 h ventilator support. He could not lift his arms against gravity, but he could use his hands to control his electric wheelchair. The muscle biopsy showed marked replacement of muscle tissue by fat and connective tissue. Only few fibers showed nemaline rods. He had a de novo, heterozygous mutation, G268D in ACTA1. Case 2 was a female patient with feeding difficulties and mild hypotonia in the neonatal period. Muscle biopsy showed hypoplastic muscle fibers and numerous rods. At 11 years of age she walked and moved unhindered and could run fairly well. She had a de novo, heterozygous mutation, K373E, in ACTA1. These two patients illustrate the marked variability in the clinical features of nemaline myopathy in spite of similar muscle pathology in early childhood. The severe muscle atrophy with replacement of fat and connective tissue in case 1 demonstrates the progressive nature of nemaline myopathy in some cases. The described two mutations add to the previously reported mutations in ACTA1 associated with nemaline myopathy.

Zonisamide for progressive myoclonus epilepsy: long-term observations in seven patients.

Progressive myoclonic epilepsy (PME) syndromes are intractable to most antiepileptic drugs (AED). The course of these diseases, results in almost total dependency due to continuous myoclonias, repeated episodes of status epilepticus, ataxia and dementia. The need for new treatment strategies is therefore imperative. Zonisamide has previously been reported to be effective in two patients with PME. Case reports of seven patients (ages 19-42) with Unverricht-Lundborgs disease (ULD) and one Lafora Body Disease are presented. Zonisamide was given at doses of 100-600 mg/day for a period of 2 to 3 years. Concomitant AEDs were usually valproate and a benzodiazepine. Zonisamide dramatically reduced the amount of myoclonias and generalized seizures. In three of the cases, the initial dramatic effect on myoclonias wore off after 2-4 years of treatment but patients still experienced moderate efficacy for generalized tonic-clonic seizures. The dramatic reduction of stimulus sensitivity for light, touch and startle by zonisamide was sustained in all patients with ULD. Zonisamide may be a useful agent in the treatment of PME. Controlled clinical trials are warranted to further investigate the antiepileptic effects of this drug, in difficult to treat epileptic syndromes.

Neurovascular microdysgenesis in a case of Unverricht-Lundborg's disease.

An 18 year old female presented with a characteristic clinical course of Unverricht-Lundborg's disease. She was treated with several antiepileptic drugs but never with phenytoin. This patient died quietly during sleep. Coronal sectioning of the fixed brain revealed a 10 mm large red-brown solid cortical-subcortical lesion in the mesial part of the right frontal lobe and a similar alteration measuring 4 mm in the centromedian nucleus of the left thalamus. Histologically the lesions displayed supernumerary irregularly oriented vessels, mainly capillaries, and, in the cortex, a markedly disturbed neuronal orientation and lamination. Numerous heterotopic nerve cells were found in the subcortical white matter, especially under the calcarine cortex. A similar vascular malformation was found in the pons. The neuropathological changes in Unverricht-Lundborg's disease have been described as non-specific atrophy of various neuronal populations, especially medial thalamic nuclei and Purkinje cells. The present case shows that the same clinical picture may be associated with multiple cerebral microvascular malformations and a disturbance in neuronal migration and organization which may be more generalized than appears in light microscopical sections.

Superoxide dismutase and glutathione peroxidase function in progressive myoclonus epilepsies.

Progressive myoclonic epilepsies (EPM) are difficult to treat and refractory to most antiepileptic drugs. Besides epilepsy, EPMs also involve continuous neurological deterioration. Oxidative stress is thought to be an important factor in this process. We therefore analyzed a series of antioxidant enzymes in the blood of patients and compared with healthy age matched controls. In addition patients were given high doses of N-acetylcysteine (NAC), a glutathione percursor to determine if symptoms of EPM would improve. Five patients, four with EPM 1 (Unverricht-Lundborg disease) and one patient with EPM2 (Lafora body disease) were treated with 6 g/day of NAC. Before treatment, plasma samples were analyzed for glutathione peroxidase activity, catalase activity, extracellular superoxide dismutase (SOD) and CuZn-SOD and compared with the controls. Erythrocyte CuZn-SOD was significantly lower in the EPM patients compared to controls. NAC improved markedly and stabilized the neurological symptoms in patients with EPM 1 but had a doubtful effect in the patient with EPM 2.

Epidemiology of mental retardation--a Swedish survey.

ecent epidemiological studies in Swedish school age children revealed a prevalence of severe mental retardation (SMR = IQ less than 50) of 0.3% and of mild mental retardation (MMR = IQ 50-70) around 0.4%. In SMR prenatal causes were found in 55%, perinatal in 15-20%, no traceable brain pathology in 18%. Corresponding figures for MMR were 23%, 18% and 55%, respectively. Down syndrome was the largest single cause of SMR and polygenic subcapacity considered to be that of MMR. Chromosomal errors were detected among 29% SMR and 4% MMR school children. Fragile X accounted for 4% SMR and 10% MMR in boys. Fetal alcohol syndromes constituted 8% of urban MMR. The contribution of inborn errors of metabolism was 4-5% and less than 1%, in SMR and MMR, respectively. Perinatal (28th prenatal week-28th postnatal day) brain damage was implicated in 15% of SMR and 18% of MMR. Pathogenetic data are considered for potential preventive measures.

Early onset dystonia decreasing with development. Case report of two children with familial myoclonic dystonia.

Two related girls had the onset of unilateral leg dystonia in the neonatal period and at 13 months, respectively. The dystonic signs subsided with motor development and resolved completely in one of the girls by the age of 5 years. There was no response to L-dopa. From 2-3 years of age segmental myoclonus with a shoulder girdle distribution appeared. Family investigation results were compatible with autosomal dominant myoclonic dystonia responsive to alcohol. The onset and resolution of dystonia have not been described previously. This disorder is genetically separate from torsion dystonia. No linkage has been found to the dopamine beta-hydroxylase gene locus. Genetically determined disorders of neurotransmission may add to our knowledge of the normal development of motor control and thus merit further study.

Infantile galactosialidosis presenting with congenital adrenal hyperplasia and renal hypertension.

A patient with early infantile galactosialidosis presenting as congenital adrenal hyperplasia with clitoral hypertrophy and arterial hypertension is reported. Serum 17-alpha-OH-progesterone and plasma renin levels were elevated. Adrenal hyperplasia and thickening of the cardiac septum were detected by sonography; however, progressive hepatosplenomegaly, increasingly coarse features, and vacuolization of bone marrow and liver cells suggested a storage disorder. Combined deficiency of beta-galactosidase and sialidase enzyme activity in both lymphocytes and cultured fibroblasts was detected. This patient with early infantile galactosialidosis is the first reported who presented with congenital adrenal hyperplasia.

PCR diagnosis of primary herpesvirus type I in poliomyelitis-like paralysis and respiratory tract disease.

Successful and rapid recovery of HSV-1 DNA from the cerebrospinal fluid after amplification by polymerase chain reaction was obtained in a 7-year-old boy with subtotal and permanent upper extremity paralysis with rapid onset and magnetic resonance imaging evidence of cervical cord involvement. Early administration of intravenous acyclovir probably limited neuronal loss. The clinical course and outcome of this disorder best conformed with what has been described as poliomyelitis-like paralysis associated with respiratory tract infection (Hopkins syndrome).

Autism in Angelman syndrome: a population-based study.

The aim of this study was to examine the prevalence of angelman syndrome in prepubertal school-aged children and analyze its comorbidity with autistic disorder. A clinical/psychiatric evaluation of a population-based sample of 6- to 13-year-old mentally retarded children with active epilepsy was performed. Four individuals in a total population of almost 49,000 children conformed to the clinical diagnosis of Angelman syndrome. Two of these had a typical microdeletion at chromosome 15q11-13. The minimum prevalence of Angelman syndrome was estimated at 0.008% (1: 12,000) in the examined age group. All 4 children with Angelman syndrome met full behavioral criteria for the diagnosis of autistic disorder/childhood autism. It is concluded that Angelman syndrome is uncommon, but more frequent than previously estimated. The diagnosis should be considered in all patients with combined autistic disorder, severe mental retardation, and epilepsy. The implications of the possible association of Angelman syndrome and autism are discussed.

[Gene amplification in viral CNS infections. Rapid diagnostic identification of herpesviruses]. / Genamplifiering vid virala CNS-infektioner. Snabb diagnostik av herpesgruppens virus.

DNA amplification with the polymerase chain reaction (PCR) technique was used as a diagnostic test on cerebrospinal fluid samples in cases where herpesvirus infection of the central nervous system (CNS) was suspected. During the period, 1992-93, 47 (8.9%) of 528 patients tested were positive for one or another of the following herpesviruses: herpes simplex virus type 1 (n = 16) or type 2 (n = 9), cytomegalovirus (n = 16), varicella-zoster virus (n = 4), or Epstein-Barr virus (n = 2). The study showed PCR to be a rapid and useful diagnostic method in clinical routine, enabling early antiviral intervention in several cases with an atypical clinical picture. Moreover, cytomegalovirus was found to be an important CNS pathogen in addition to herpes simplex virus, especially during childhood.