CLN5, a novel gene encoding a putative transmembrane protein mutated in Finnish variant late infantile neuronal ceroid lipofuscinosis.

The neuronal ceroid lipofuscinoses (NCLs) represent a group of common recessive inherited neurodegenerative disorders of childhood, with an incidence of 1:12,500 live births. They are characterized by accumulation of autofluorescent lipopigments in various tissues. Several forms of NCLs have been identified, based on age at onset, progression of disease, neurophysiological and histopathological findings and separate genetic loci. All types of NCL cause progressive visual and mental decline, motor disturbance, epilepsy and behavioral changes, and lead to premature death. One of the subtypes, Finnish variant late infantile neuronal ceroid lipofuscinosis (vLINCL; MIM256731) affects children at 4-7 years of age. The first symptom is motor clumsiness, followed by progressive visual failure, mental and motor deterioration and later by myoclonia and seizures. We have previously reported linkage for vLINCL on chromosome 13 (ref. 5) and constructed a long-range physical map over the region. Here, we report the positional cloning of a novel gene, CLN5, underlying this severe neurological disorder. The gene encodes a putative transmembrane protein which shows no homology to previously reported proteins. Sequence analysis of DNA samples from patients with three different haplotypes revealed three mutations; one deletion, one nonsense and one missense mutation, suggesting that mutations in this gene are responsible for vLINCL.

Juvenile-onset neuronal ceroid lipofuscinosis with infantile CLN1 mutation and palmitoyl-protein thioesterase deficiency.

Accurate diagnosis, especially in progressive hereditary diseases, is essential for the treatment and genetic counseling of the patient and the family. Neuronal ceroid lipofuscinoses (NCL) are amongst the most common groups of neurodegenerative diseases. Infantile, juvenile, and adult-onset types with multiple genotype-phenotype associations have been described. A fluorimetric enzyme assay for palmitoyl protein thioesterase (PPT) from leukocytes and fibroblasts has been previously developed to confirm the diagnosis of infantile NCL. We describe a patient with juvenile-onset NCL phenotype with a new CLN1 mutation and deficient PPT activity. Over 40 different mutations have been found in patients with PPT deficiency, indicating that screening for known mutations is not an efficient way to diagnose this disorder. Therefore, PPT enzyme analysis should precede mutation analysis in suspected PPT deficiency, particularly in patients with granular osmiophilic deposits (GROD) or in patients who have negative ultrastructural data. The use of enzyme assay led to the diagnosis of this patient with juvenile-onset Finnish variant NCL with PPT deficiency, and we expect that greater awareness of the utility of the enzymatic assay may lead to identification of other similar cases awaiting a definitive diagnosis.

Variant late infantile neuronal ceroid-lipofuscinosis: pathology and biochemistry.

The neuronal ceroid-lipofuscinoses (NCL) are among the most common inherited neurodegenerative disorders of childhood. The genomic defect causing a variant late infantile neuronal ceroid-lipofuscinosis (vLINCL, also called CLN-5 or variant Jansky-Bielschowsky disease) has recently been localized to chromosome 13q22, thus delineating this disease as a separate entity. This particular form of NCL is clinically well defined, but lacks pathomorphological and biochemical description. The present analyses indicate that subunit c of the mitochondrial ATP synthase is the major protein in vLINCL brain storage cytosomes. These cytosomes also contain minor amounts of sphingolipid activator proteins (SAPs). The immunohistological distribution of subunit c and SAPs in the central nervous system (CNS) and visceral tissues closely resembles that of classical LINCL. Thus, despite clinical differences and the fact that various forms of NCL are caused by different genetic defects, variant and classical LINCL as well as juvenile NCL are all characterized by pronounced lysosomal accumulation of the same hydrophobic protein, subunit c of the mitochondrial ATP synthase.

Absence seizures: valproate or ethosuximide?

A series of 47 children with absence seizures was analysed retrospectively. Fourteen of these children also had other types of seizures, and four had repeated episodes of absence status. The age at onset of absence seizures ranged from 1 1/2 to 13 years (mean, 7.9 years). The mean follow-up was 5.5 years. Ethosuximide (ESM) was used as the drug of first choice in 43 children, and valproate (VPA) was used first in 4 children; 15 of the patients later received VPA alone or in combination with ESM. A 100% reduction in seizure frequency was achieved in 38 children (80.8%). Of these, 23 has received ESM (21 ESM; 2 ESM + nitrazepam) and 15 had received VPA (6 VPA; 9 VPA + ESM). Of the latter group, 11 children had had an unsuccessful trial of ESM. VPA was superior in the treatment of children who had EEG polyspikes or absence status. A seizure reduction of 50% to 75% was achieved in 7 children (14.9%). Two patients (4.3%) had refractory seizures. A transient Stevens-Johnson syndrome occurred in a patient treated with ESM. Other side effects were mild and transient. Both ESM and VPA are needed in the treatment of absence seizures. In refractory cases, the combination of these drugs appears to be beneficial.

A single PCR marker in strong allelic association with the infantile form of neuronal ceroid lipofuscinosis facilitates reliable prenatal diagnostics and disease carrier identification.

The infantile form of neuronal ceroid lipofuscinosis (INCL) is a progressive encephalopathy in children < 2 years old. The disease is one of the Finnish diseases, enriched in this genetically isolated population. The gene responsible for INCL has been recently assigned to the short arm of human chromosome 1. Here we describe DNA-based prenatal and carrier diagnostics using a highly polymorphic marker (HY-TM1) which demonstrates a strong allelic association to the disease locus. 88% of Finnish INCL patients were observed to have the same affected genotype, suggesting that one major CLN1 mutation is enriched in this population. In contrast, all the non-Finnish INCL patients had different allele combinations.

Evaluation of the possible role of coenzyme Q10 and vitamin E in juvenile neuronal ceroid-lipofuscinosis (JNCL).

The juvenile type of neuronal ceroid lipofuscinosis (JNCL) is a recessively inherited, progressive neurodegenerative disease. In this study the levels of the antioxidant factors coenzyme Q10 (CoQ10) and vitamin E (alpha-tocopherol) were measured in plasma samples of 29 JNCL patients and compared to 48 healthy controls. A significant reduction of the coenzyme Q10 level (0.59 +/- 0.25 microgram/ml) was observed in JNCL patients when compared to control subjects (0.80 +/- 0.26 microgram/ml). The level of vitamin E was also reduced markedly in JNCL patients when compared to controls (10.4 +/- 4.1 and 12.1 +/- 4.5 micrograms/ml, respectively). The low levels of CoQ10 and vitamin E in JNCL patients may indicate an impaired antioxidant protection in this disease.

Sumatriptan for migraine attacks in children: a randomized placebo-controlled study. Do children with migraine respond to oral sumatriptan differently from adults?

Oral sumatriptan is an effective acute treatment for migraine in adults, but its efficacy in children is still undetermined. Twenty-three children, aged 8.3 to 16.4 years, took both sumatriptan and placebo in a randomized, double-blind, placebo-controlled, crossover trial. The primary endpoint was a > or = 50% decrease in pain intensity on a 100-mm visual analogue scale at 2 hours. Other endpoints of efficacy were pain intensity difference (PID), showing pain relief at each time point; summed pain intensity differences (SPIDs), estimating overall pain relief; and preference. Two hours after sumatriptan, 7 of 23 reached the primary endpoint, and after placebo, 5 of 23 (difference 9%, 95% CI for difference, -21 to 38%; p = ns). Within 2 hours, the headache disappeared completely in 5 of 23 children after sumatriptan and in 2 of 23 children after placebo (p = ns). Median PIDs were slightly better for sumatriptan between 0.5 and 4 hours (p = ns). Median SPIDs increased almost identically up to 2 hours. Thereafter, median SPIDs for placebo remained practically constant, whereas for sumatriptan, the improvement continued. At 4 hours, the median SPID for sumatriptan was 2.4 times as high as for placebo. However, the maximum differences between median SPIDs at 4 hours (38.5, 95% CI, -75.8 to 57.5; Wilcoxon signed rank test, p = 0.4) or at any other point were not statistically significant. Of the 23 children, 13 preferred sumatriptan and 2 placebo (sign test, p = 0.004). The failure of this and previous controlled studies suggests that the response of children to sumatriptan may be different from adults.

A favorable response to antiparkinsonian treatment in juvenile neuronal ceroid lipofuscinosis.

To study the effect of dopaminergic drugs on the parkinsonism in juvenile neuronal ceroid lipofuscinosis, the authors conducted an open study of 21 patients. According to the motor Unified PD Rating Scale (UPDRS) score, treatment was initiated with either levodopa (n = 10) or selegiline (n = 6). Five patients served as a control group. The UPDRS score after 1 year was compared with the score at onset. Both in the control group and in the selegiline group, the mean UPDRS score increased, whereas in the levodopa group, the mean UPDRS score decreased. The difference between the levodopa group and the control group was significant.

Ibuprofen or acetaminophen for the acute treatment of migraine in children: a double-blind, randomized, placebo-controlled, crossover study.

Efficacy of drugs for the acute treatment of migraine in children has not so far been studied in well controlled trials. We conducted a study to evaluate the efficacy of acetaminophen and ibuprofen. Eighty-eight children, aged 4.0 to 15.8 years, with migraine participated in a double-blind crossover study. Three attacks per child were treated in random order with single oral doses of 15 mg/kg acetaminophen, 10 mg/kg ibuprofen, and placebo at home. The primary end point, reduction in severe or moderate headache (grade > or = 3 on a scale of 1 to 5) by at least two grades after 2 hours, was reached twice as often with acetaminophen and three times as often with ibuprofen as with placebo. Ibuprofen was twice as likely as acetaminophen to abort migraine within 2 hours. In the intent-to-treat analysis, children improved twice as often with ibuprofen and acetaminophen as with placebo. Both ibuprofen and acetaminophen are effective and economical treatments for severe or moderate migraine attacks in children. Ibuprofen gave the best relief.

CSF insulin-like growth factor-1 in infantile neuronal ceroid lipofuscinosis.

BACKGROUND: Infantile neuronal ceroid lipofuscinosis (INCL) is a progressive encephalopathy in which the patients are severely disabled by the age of 3 years. It is characterized by cerebral atrophy, selective loss of cortical neurons, and secondary loss of axons and myelin sheaths of the white matter. INCL has been shown to result from a palmitoyl protein thioesterase deficiency. The authors suggested that insulin-like growth hormones and apoptosis might play a role in the pathogenesis of INCL. METHODS: The authors measured insulin-like growth factor-1 (IGF-1) and IGF binding protein 3 (IGFBP-3) in the CSF of patients with INCL by radioimmunoassay at an early stage when myelin was starting to diminish. RESULTS: The authors found low CSF IGF-1 but normal IGFBP-3 in patients with INCL compared with control subjects. Also, they observed apoptotic cell death in biopsies of INCL patients. CONCLUSIONS: Because the IGF system seems to be important for early brain development, myelination, and neuroprotection, the authors suggest that the pathology in INCL may be associated with low CSF IGF-1.

Decreased striatal dopamine transporter density in JNCL patients with parkinsonian symptoms.

OBJECTIVE: To explore whether striatal dopamine transporters are involved in juvenile neuronal ceroid lipofuscinosis (JNCL) with extrapyramidal signs. METHODS: Seventeen patients with JNCL entered the study (mean age, 15 years; age range, 10 to 31 years). For clinical evaluation, the authors used the motor section of the Unified Parkinson's Disease Rating Scale (UPDRS). For studying the density of dopamine transporters in the striatum, they employed iodine-123-labeled 2beta-carbomethoxy-3beta-(4-iodophenyl) tropane as a SPECT tracer. The SPECT images were evaluated visually, and tracer accumulation was semiquantified from transverse slices as striatum-to-cerebellum activity ratios. MRI (1.5-T) signal intensities of the striatum were measured and compared with those of the thalamus. RESULTS: The mean UPDRS score was 20 (range, 2 to 41). On SPECT, the mean striatum-to-cerebellum uptake ratio was lower in patients than in control subjects (3.1 +/- 0.6 versus 6.8 +/- 1.0; p < 0.001), with the decrease being more pronounced in the putamen than in the caudate nucleus. On MRI, the mean striatum-to-thalamus signal intensity ratio was higher in patients than in control subjects (1.14 +/- 0.02 versus 1.08 +/- 0.02; p < 0.001). There was a negative correlation between uptake ratios in SPECT and UPDRS scores, and a positive correlation between the MRI ratios and UPDRS. The SPECT and MRI ratios also correlated significantly, providing additional evidence for the contributions of nigrostriatal, striatal, and thalamic dysfunction to the parkinsonian symptoms. CONCLUSIONS: The observed decrease in the striatal dopamine transporter density in JNCL offers a rational basis for a trial of dopaminergic drugs in this disease.

Bright light suppresses melatonin in blind patients with neuronal ceroid-lipofuscinoses.

We studied whether light information can reach the pineal glands of clinically blind patients with neuronal ceroid-lipofuscinoses. The suppression of melatonin by light was used as an indicator. Seven patients and seven control subjects were exposed to 3,000-lux light for 60 minutes at the rising phase of the melatonin synthesis. Most patients were not cooperative, and their eyelids were opened by a researcher every 2 minutes for 2 seconds. The control subjects opened and closed their eyes similarly by themselves. Light suppressed melatonin in three of seven control subjects and in all patients. The average postlight levels were 80% (control subjects) and 51% (patients) of the corresponding levels during the dim-light session. Despite degenerated retinas of the blind patients, light can penetrate their visual system to the hypothalamic and pineal levels and regulate neuroendocrine function.

Hematopoietic stem cell transplantation in infantile neuronal ceroid lipofuscinosis.

OBJECTIVE: To study the effect of allogeneic hematopoietic stem cell transplantation (SCT) on the clinical course of infantile neuronal ceroid lipofuscinosis (INCL), a lysosomal storage disease. BACKGROUND: INCL is a progressive encephalopathy with severe neuronal loss, especially in the cerebral and cerebellar cortex and retina. Autofluorescent lipopigments constitute the typical storage material in INCL. The disease is caused by recessive mutations in the palmitoyl protein thioesterase 1 (PPT1) gene. PPT1 is a depalmitoylating enzyme, which is transported to lysosomes through the mannose-6-phosphate receptor-mediated pathway, and participates in the lysosomal degradation of fatty acylated proteins. METHODS: Three patients with INCL received transplants and were followed up after SCT at the Hospital for Children and Adolescents at the University of Helsinki. The first patient rejected the first graft at the age of 7 months and had mild symptoms of INCL at the second transplantation at 11 months. The two other patients were asymptomatic when they received their transplants at the age of 4 months. RESULTS: PPT1 enzyme activity was normalized in peripheral leukocytes, but remained low in the CSF and resulted only in a mild and transient amelioration of the classic INCL. All patients who received transplants developed INCL by the age of 2 or 3 years. CONCLUSIONS: More experimental animal and cell culture studies are needed to determine the in vivo function of PPT1. SCT currently cannot be recommended as therapy for INCL.

Phenotype-genotype correlation in eight patients with Finnish variant late infantile NCL (CLN5).

The authors analyzed the clinical phenotype, including MRI, of eight patients with Finnish variant late infantile neuronal ceroid lipofuscinosis (vLINCLFin; CLN5; MIM256731). Although the four known mutations, including one novel mutation identified in this study, have very different consequences for the predicted polypeptide, none of them results in an atypical phenotype, as has been reported in other forms of NCL. Thus, it seems likely that each mutation severely disturbs the normal function of the CLN5 protein.

Clinical and genetic distinction between Walker-Warburg syndrome and muscle-eye-brain disease.

BACKGROUND: Three rare autosomal recessive disorders share the combination of congenital muscular dystrophy and brain malformations including a neuronal migration defect: muscle-eye-brain disease (MEB), Walker-Warburg syndrome (WWS), and Fukuyama congenital muscular dystrophy (FCMD). In addition, ocular abnormalities are a constant feature in MEB and WWS. Lack of consistent ocular abnormalities in FCMD has allowed a clear clinical demarcation of this syndrome, whereas the phenotypic distinction between MEB and WWS has remained controversial. The MEB gene is located on chromosome 1p32-p34. OBJECTIVES: To establish distinguishing diagnostic criteria for MEB and WWS and to determine whether MEB and WWS are allelic disorders. METHODS: The authors undertook clinical characterization followed by linkage analysis in 19 MEB/WWS families with 29 affected individuals. With use of clinical diagnostic criteria based on Finnish patients with MEB, each patient was categorized as having either MEB or WWS. A linkage and haplotype analysis using 10 markers spanning the MEB locus was performed on the entire family resource. RESULTS: Patients in 11 families were classified as having MEB and in 8 families as WWS. Strong evidence in favor of genetic heterogeneity was obtained in the 19 families. There was evidence for linkage to 1p32-p34 in all but 1 of the 11 pedigrees segregating the MEB phenotype. In contrast, linkage to the MEB locus was excluded in seven of eight of the WWS families. CONCLUSION: These results allow the classification of MEB and WWS as distinct disorders on both clinical and genetic grounds and provide a basis for the mapping of the WWS gene(s).

Delayed classic and protracted phenotypes of compound heterozygous juvenile neuronal ceroid lipofuscinosis.

OBJECTIVE: To correlate the phenotypes with the genotypes of 10 Finnish juvenile neuronal ceroid lipofuscinosis (JNCL; late-onset Batten disease) patients who all are compound heterozygotes for the major 1.02-kb deletion in the CLN3 gene. METHODS: The mutations on the non-1.02-kb deletion chromosomes were screened in 6 patients; in the other 4 patients the mutations were known (one affecting a splice site, two missense mutations, and one deletion of exons 10 through 13). Clinical features were examined, and MRI, MRS, somatosensory evoked magnetic field (SEF), and overnight polysomnography (PSG) studies were performed. RESULTS: A novel deletion of exons 10 through 13 was found in 6 patients belonging to three families. In the patients carrying the deletions of exons 10 through 13 the clinical course of the disease was fairly similar. Variation was greatest in the time course to blindness. In these patients the mental and motor decline was slower than in classic JNCL, but more severe than in the two patients with missense mutations in exons 11 and 13. MRI showed brain atrophy in 4 patients. One patient had hyperintense periventricular white matter, otherwise brain signal intensities were normal. SEFs were enhanced in patients older than 14 years, whereas in PSG all but the youngest 6-year-old patient showed epileptiform activity in slow-wave sleep. CONCLUSIONS: JNCL can manifest as at least three different phenotypes: classic, delayed classic, and protracted JNCL with predominantly ocular symptoms. Finnish compound heterozygotes have the delayed classic or the protracted form of JNCL.

Muscle-eye-brain disease and Fukuyama type congenital muscular dystrophy are not allelic.

Muscle-Eye-Brain disease (MEB) and Fukuyama type congenital muscular dystrophy (FCMD) are clinically similar autosomal recessive diseases, characterized by congenital muscular dystrophy and severe mental retardation, raising the possibility that they might be caused by mutations of the same gene. Recently FCMD was localized to chromosome 9q31-33 by linkage. We performed a linkage study in seven Finnish MEB families with 12 affected patients using markers D9S53, D9S58, D9S59 and HXB. The MEB phenotype was not linked to any of the markers. A multipoint linkage analysis excluded the entire region harboring FCMD. We thus conclude that MEB and FCMD are not allelic.

Muscle membrane-skeleton protein changes and histopathological characterization of muscle-eye-brain disease.

Muscle-eye-brain disease belongs to congenital muscular dystrophies with central nervous system abnormalities. The etiology of MEB is still unknown, but abnormal immunoreactivity for laminin-2 has been reported. To evaluate disease progression in muscle tissue, 32 biopsy specimens from 17 muscle-eye-brain patients were analysed. The samples of four patients were studied by immunohistochemical techniques and by quantitative Western blotting. The samples showed a great variation in the muscle pathology. Regenerative fibers and mild fiber size variation were present in over 60%. At infancy, necrotic and regenerative fibers were common, while fat infiltration was the most prominent finding in the age group over five years. In quantitative studies, the amount of laminin alpha 2 chain was clearly reduced to 10-20% of normal. In contrast, laminin beta 2 chain was overexpressed in the Western blotting studies. These findings may reflect a yet unidentified primary disturbance in the basement membrane composition and function.

Palmitate oxidation in muscle mitochondria of patients with the juvenile form of neuronal ceroid-lipofuscinosis.

The finding that the intracellular storage material in juvenile neuronal ceroid lipofuscinosis (JNCL) consists of the subunit c of ATP synthase prompted us to study energy conservation in JNCL patients. The activities of respiratory chain enzymes in isolated muscle mitochondria from 8 JNCL cases were normal, but oxidation of palmitate was reduced in 6 patients. The degree of reduction was related to the age of the patients. None of the patients had clinical symptoms or laboratory findings of impaired energy conservation, which suggest that the reduced palmitate oxidation was not associated with a major defect in fatty acid oxidation.

Linkage map of the chromosomal region surrounding the infantile neuronal ceroid lipofuscinosis on 1p.

The neuronal ceroid lipofuscinoses (NCLs) of childhood are divided into 3 main types according to age-of-onset, clinical course, and neurophysiological and neuropathological findings: infantile, late infantile, and juvenile. All forms are inherited as an autosomal recessive trait, and their biochemical background is still unknown. The infantile type (INCL) with the earliest age-of-onset and the most severe clinical course, occurs in Finland with an incidence of 1:20,000, i.e., 116 patients have been found in our country up to now, whereas only about 50 cases have been reported from other parts of the world. Earlier we reported the linkage of INCL to the short arm of chromosome 1. Here we describe a more precise linkage map of this area. Our current map places the INCL mutation between D1S57 and D1S79; D1S7 has so far shown no recombination events between the marker and the disease (lod score 4.55 at theta = 0.00). Our material includes 64% of all living patients in Finland, and no linkage disequilibrium of haplotypes is seen, using the 2 physically close markers D1S57 and D1S79. This finding as well as our LINKMAP analyses suggest that the distance between the disease locus and the flanking markers is about 3-4 cm.