The molecular basis of canavan (aspartoacylase deficiency) disease in European non-Jewish patients

Canavan disease is an infantile neurodegenerative disease that is due to aspartoacylase deficiency. The disease has been reported mainly in Ashkenazi Jews but also occurs in other ethnic groups. Determination of enzymatic activity for carrier detection and prenatal diagnosis is considered unreliable. In the present study, nine mutations were found in the aspartoacylase gene of 19 non-Jewish patients. These included four point mutations (A305E [39.5% of the mutated alleles], C218X [15.8%], F295S [2.6%], and G274R [5.3%]); four deletion mutations (827delGT [5.3%], 870del4 [2.6%], 566del7 [2.6%], and 527del6 [2.6%]); and one exon skip (527del108 [5.3%]). The A305E mutation is pan-European and probably the most ancient mutation, identified in patients of Greek, Polish, Danish, French, Spanish, Italian, and British origin. In contrast, the G274R and 527del108 mutations were found only in patients of Turkish origin, and the C218X mutation was identified only in patients of Gypsy origin. Homozygosity for the A305E mutation was identified in patients with both the severe and the mild forms of Canavan disease. Mutations were identified in 31 of the 38 alleles, resulting in an overall detection rate of 81.6%. All nine mutations identified in non-Jewish patients reside in exons 4-6 of the aspartoacylase gene. The results would enable accurate genetic counseling in the families of 13 (68.4%) of 19 patients, in whom two mutations were identified in the aspartoacylase cDNA.

Mutations in the X-linked E1 alpha subunit of pyruvate dehydrogenase: exon skipping, insertion of duplicate sequence, and missense mutations leading to the deficiency of the pyruvate dehydrogenase complex

Human pyruvate dehydrogenase (PDH)-complex deficiency is an inborn error of metabolism that is extremely heterogeneous in its presentation and clinical course. In a study of 14 patients (7 females and 7 males), we have found a mutation in the coding region of the E1 alpha gene in all 14 patients. Two female patients had the same 7-bp deletion at nt 927; another female patient had a 3-bp deletion at nt 931. Another female patient was found to have a deletion of exon 6 in her cDNA. Two other female patients were found to have insertions, one of 13 bp at nt 981 and one of 46 bp at nucleotide 1078. Two male patients were found to have a 4-bp insertion at nucleotide 1163. The remaining six patients all had missense mutations. A male patient and a female patient both had an A1133G mutation. The other missense mutations were C214T, C615A, and C787G (two patients). Five of these mutations are novel mutations, five have been previously reported in other patients, and two were published observations in other patients in an E1 alpha-mutation summary. In the four cases where parent DNA was available, only one mother was found to be a carrier of the same mutation as her child.

Cerebral glucose metabolism in neurofibromatosis type 1 assessed with [18F]-2-fluoro-2-deoxy-D-glucose and PET

Cerebral PET with [18F]-2-fluoro-2-deoxy-D-glucose has been performed in four patients with neurofibromatosis type 1 (NF1) to assess the relation between cerebral metabolic activity, MRI, and the presence of neurological symptoms, including seizures, as well as mental and language retardation. Widespread hypometabolism occurred in three of the patients. The lesions on MRI, which were localised in the subcortical white matter and grey structures, had normal rates of glucose metabolism. This finding suggests that the abnormalities seen on MRI are not due to defective blood supply, localised oedema, or grey matter heterotopic foci as previously hypothesised. The presence of the hypometabolic areas seems to be inconsistently related to the occurrence of seizures and is not proportional to the degree of mental impairment. This study provides evidence of a widespread cerebral hypometabolism that is not related to the presence of MRI abnormalities; conversely normal metabolism was present in the areas with an abnormal MRI signal.

Celiac disease and epilepsy in pediatric patients

Among 783 patients referred to our institute with different types of seizures as presenting symptom, systematic evaluation of antigliadin and antiendomysial antibodies in the serum has identified nine in whom jejunal biopsy has subsequently confirmed the diagnosis of celiac disease (CD). In three of them brain imaging showed the presence of calcified areas in the occipital region. They had complex partial seizures (CPS), associated in two with transient episodes of blindness. In another patient with CPS and generalized tonic-clonic seizures (GTCS) progressive multifocal cerebral calcifications were noted. In the other six patients with CPS and/or GTCS cerebral calcifications were absent. Symptoms of CD in all these cases were either not previously taken into account, or they were very mild or completely absent. In a group of 36 patients with clinically manifest CD, regular follow-up, and good compliance with the dietary regimen, no clinical seizures were reported. The pathogenetic mechanism and the relationship between epilepsy and an early diagnosis and treatment of celiac disease are discussed.

Vigabatrin treatment in children

Sixty-nine children, aged from 2 months to 16 years and suffering from different types of drug-resistant epileptic seizures, mostly complex partial and secondary generalised, were recruited in an open, uncontrolled, prospective study of treatment with vigabatrin (gamma-vinyl GABA). Following a 3-month baseline observation period, the initial dose of vigabatrin of 10 mg/kg per day was progressively increased up to a maximum of 140 mg/kg per day, in addition to the conventional concomitant therapy. Sixteen patients showed a > or = 50% reduction in seizure frequency compared with the baseline, with complete control of seizures in nine cases. In 14 other patients, no substantial change in seizure frequency was observed, although an improvement in psychological performance after vigabatrin treatment warranted further continuation of the drug. In 35 patients vigabatrin was discontinued because of lack of efficacy (22 cases) and/or increased seizure frequency (13 cases). The clinical and biological tolerance of vigabatrin was remarkably good.

Infantile spasms in patients with neurofibromatosis type 1

The authors report two patients with neurofibromatosis type 1 who were affected by infantile spasms. The infantile spasms were severe and unresponsive to anticonvulsant treatment. The authors maintain that infantile spasms may belong to the clinical features of neurofibromatosis type 1.

Central nervous system imaging in reevaluation of patients with neurofibromatosis type 1

We report the results of the reevaluation of 24 patients with neurofibromatosis type 1 (NF1) using central nervous system (CNS) imaging techniques. The first examination by computed tomography (CT) or magnetic resonance imaging (MRI) indicated the presence of optic glioma in three cases, "unidentified bright objects" (UBOs) in six, and a suspected right frontal tumor in one. In two patients optic glioma and UBOs were both present and in one of them a bulbar tumor was also suspected. Later imaging examinations revealed the appearance of optic glioma in three more cases and UBOs in nine. In two of these patients both optic glioma and UBOs were present. This study indicates that the likelihood of detecting imaging abnormalities in patients with NF1 increases when systematic follow-up is performed. Optic gliomas are characteristic of pediatric patients; they rarely give rise to clinical manifestations (1/6 cases) and in general progress very slowly. For these reasons, therapeutic strategy must be carefully considered and individually decided. UBOs are very frequent findings in pediatric patients with NF 1 and therefore they must be considered diagnostically relevant. They are not related to clinical manifestations and spontaneous regression has been observed. The nature of these imaging abnormalities is still unknown, but because they do not behave like tumors, useless and dangerous therapeutic procedures should not be employed.

Relationship between café-au-lait spots as the only symptom and peripheral neurofibromatosis (NF1): a follow-up study

We re-examined 21 children with the possible diagnosis of peripheral neurofibromatosis (NF1) based on the presence of café-au-lait (CAL) spots as the single clinical finding. We evaluated whether "typical" or "atypical" appearance of the spots was important for the final diagnosis and whether the co-existence of other non-specific signs (e.g. pectus excavatum) were of any significance for the final diagnosis. In 8/14 (57.1%) cases with "typical" CAL spots, the diagnosis of NF1 was finally established on the basis of other criteria. For the other 6 patients the diagnosis is not yet definitive but highly probable on the basis of the presence of macrocephaly, pectus excavatum and/or MRI findings. Only one patient among five with "atypical" CAL spots possibly has NF1.

Diagnosis of neurofibromatosis type 1 using RFLPs tightly linked to gene

This study reports the results of a linkage analysis in nine families with members who had neurofibromatosis type 1 (NF1), using five restriction fragment length polymorphisms (RFLPs) tightly linked to the NF1 locus. The purpose of this analysis was to determine whether the at-risk individuals were carrying the NF1 allele and whether the nine families would be informative for prenatal testing. The families included 25 patients with NF1, 3 individuals at risk for NF1, and 11 unaffected subjects, with a total of 39 family members and 12 matings. In 6 matings two or more flanking probes were informative, in 3 matings only one probe was informative, and in the other 3 no probe was informative. DNA linkage analysis showed with more than 98% probability that the 3 at-risk individuals did not carry the NF1 mutation. No recombination events were observed. In 6 families it will be possible to do a DNA prenatal diagnosis if this type of test is requested. The NF1 gene has been identified and direct testing for the NF1 mutation is now possible. Linkage testing, however, will probably remain useful and complementary to direct analysis of the NF1 gene to reveal intragenic recombination events and for diagnosis in families in which the detection of mutation is difficult.

Progressive cerebral calcifications, epilepsy, and celiac disease

A case with progressive cerebral calcifications, white matter involvement, and drug-resistant epilepsy in a 9-year-old boy is described. The final diagnosis was celiac disease (CD). The relationship of CD with epileptogenic lesions is considered, and the possible significance of this association is discussed.

Biochemical diagnosis of Canavan disease

Canavan disease (CD) is a rare autosomal recessive disorder characterized by macrocephaly and progressive leukodystrophy. Up to now biopsy or necropsy were required to define the diagnosis. Recently the disease has been related to N-acetylaspartic aciduria and deficiency of aspartoacylase, an enzyme possibly involved in the myelin synthesis. These biochemical findings have provided a diagnostic marker for the disease. We report a new case of infantile CD in which the demonstration of N-acetylaspartic aciduria and a marked deficiency of aspartoacylase activity confirmed the diagnosis.

Molecular study in von Recklinghausen neurofibromatosis (NF1)

The von Recklinghausen neurofibromatosis (NF1) gene has been mapped to the pericentromeric region of chromosome 17 and various DNA markers have been identified in this region. We have performed a genetic analysis using an anonymous DNA marker, HHH202 (D17S33), tightly linked to the NF1 gene in seven NF1 Italian families. Only one family was fully informative for the HHH202/RsaI polymorphism. In this family this marker can be used for presymptomatic and prenatal diagnosis. However, it is necessary to use additional flanking markers in order to increase informativeness and to obtain better diagnostic accuracy.

Use of intravenous immunoglobulins in drug-resistant epilepsy

Among the 257 pediatric patients examined, 104 were classified as having drug-resistant epilepsy (DRE). In all of them genetic, metabolic, chromosomal and infectious causes were investigated, and brain imaging with computed tomography scans and nuclear magnetic resonance were obtained. Since treatment with gammaglobulins (GGs) has been reported to be useful in pediatric cases of epilepsy, informed consent for GGs treatment was obtained in 43 patients with DRE. The etiology or evidence of brain lesions was identified in 16 of them. In 31 of these patients, neither conventional drug treatment, nor a trial with adrenocorticotropic hormone was successful. Intact monomeric GGs, 400 mg/kg, were given intravenously. A second dose was given after 15 days and, thereafter, every 21 days for a maximum of ten injections (protocol A), or every 2nd day for a maximum of five doses (protocol B). In every patient, the type of epilepsy was identified according to the classification of the International League Against Epilepsy. The frequency of seizures was recorded for a period beginning at least 6 months before the administration of GGs. Immunological evaluation was also performed before and after the treatment with GGs. A transient decrease of the seizure frequency was noted in 12 subjects. In another patient with infantile idiopathic myoclonic epilepsy, seizures disappeared for 30 months. In 1 case a persistent 80% reduction in the number of seizures was observed. A persistent disappearance of seizures was noted in a subject with complex partial seizures (CPS) that followed an idiopathic infantile spasm syndrome.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical findings in children with occipital paroxysmal discharges

Occipital paroxysmal discharges (OPDs) have been related to a variety of clinical problems. To evaluate associated symptoms and patient outcome, we studied 293 children with OPDs. Follow-up of more than 6 months was available in 141 children. Mental retardation, neurological symptoms, behavior problems, ocular symptoms, and convulsions of various types were present. Eight patients had ictal visual phenomena consistent with the diagnosis of benign epilepsy with occipital spike and wave (BEOSW). In the 141 children with at least 6 months follow-up, 58 had other types of convulsions. Clinical and EEG normalization was observed in 25 and clinical normalization only in 17. The use of antiepileptic drugs did not seem to influence the outcome although seizure control was obtained in 26 patients. In all the cases where follow-up was 9 or more years, clinical normalization was observed. Clinical symptoms in these patients were quite heterogeneous and frequently not ictal. The disappearance of OPDs with increasing age points to their being "not lesional" in origin.

Chromosome abnormalities in tuberous sclerosis

In fibroblasts cultured from biopsies of the skin lesions of six patients with tuberous sclerosis (TS) there was a variable but consistent degree of karyotypic variation. Premature centromere disjunction (PCD) of all or part of the chromosomes, micronuclei, an increased incidence of breaks, dicentric chromosomes and the presence of polyploid metaphases were found in all cultures. The PCD was of the type encountered in Roberts syndrome and its frequency varied from 8% to 30%. In metaphases with PCD of one and of two chromosomes, the chromosome involved were identified, and chromosome 3 was involved 21 times among 59 chromosomes with PCD. Chromosome 3 tends to be preferentially involved in dicentric formation. In lymphocyte cultures from the same patients there were no metaphases with PCD, but there was a slight increase of breaks and the presence of dicentric chromosomes, also involving chromosome 3. Polyploid metaphases were increased in some of the cases. Karyotypic variation can be considered a cellular phenotypic characteristic of TS in fibroblasts cultured from the skin lesions, and its type indicates disturbances in the mechanics of centromere division and of chromosome distribution at cell division.

Trichothiodystrophy without photosensitivity. Biochemical, ultrastructural and DNA repair studies

A case of trichothiodystrophy (TTD) without photosensitivity is reported in an 8-year-old girl. Electron microscopic (EM) examination of the keratinocytes showed fibrillary bundles in the cytoplasm thinner and less electron dense than those of the normal cells and large membrane-bound vacuoles filled with granular-filamentous material. These findings could indicate a disturbance in the protein metabolism in tissues of ectodermal origin, explaining also the functional abnormalities of the central nervous system in TTD patients. The results of cellular DNA repair studies after UV irradiation in cultured fibroblasts showed normal levels of unscheduled DNA synthesis. This finding indicates that UV hypersensitivity is not constantly present in TTD.

Intractable epilepsy: etiology, risk factors and treatment

The data emerging from our study are the following: the presence of an identifiable cause is important: complications like tuberous sclerosis or signs of marked cerebral damage represent an adverse risk factor for IE. The presence of epilepsy among relatives, evidence of pre- or perinatal cerebral damage, mental retardation, and early onset, long periods of uncontrolled seizures before starting an adequate therapy and frequency of seizures appear to be indicative of an adverse prognosis, since differences between the two groups of responsive or unresponsive patients are statistically significant. On the contrary, the occurrence of febrile convulsions in the past history does not seem to have an adverse prognosis. Temporal lobe epilepsy and IS bear the worst prognosis. ME, CPS, GTCS, SPS, LGS and PM have a progressively better outcome in responsiveness to AEDs. Concerning therapy in patients with IE, studies indicate the results of high dose monotherapy appear to be equal or better than with polypharmacy. Because of the gravity of the situation, trials with unconventional drugs have been performed, but it is too early to draw definite conclusions about the long-term usefulness of most of them. In conclusion, our data indicate that the appearance of an IE can be predicted utilizing the above mentioned criteria, considered either alone or in combination. The issue of IE remains undoubtedly an important one among the group of convulsive disorders. Further studies considering a greater number of patients and new therpeutic strategies are to be recommended.

First trimester prenatal diagnosis of Sanfilippo disease (MPSIII) type B

Two pregnancies of a family at risk for Sanfilippo disease type B were monitored in the first trimester. In one case an affected fetus was diagnosed on chorionic villi by the assay of N-acetyl-alpha-D-glucosaminidase and confirmed on cultured fibroblasts from the aborted fetus. Pathological findings are also reported and compared with changes observed later in life. The disease was excluded in the second pregnancy.

Free sialic acid storage disease. A new Italian case

Increased amounts of free sialic acid were found in cultured fibroblasts and urine of a 4-year-7-month-old Italian boy with mental retardation, hypotonia, failure to thrive, coarse facial features, convergent strabismus, pale skin and fair hair. Ultramicroscopic examination of conjunctival and skin tissues showed a number of membrane-bound vacuoles containing low-density granular material in the cytoplasm of the fibroblasts. The clinical, biochemical and ultrastructural findings are similar to those described in Salla disease. Neuraminidase activity is normal. The molecular basis of the sialic acid storage disease is not known. Evidence for defective transport of sialic acid across the lysosomal membrane has been demonstrated in the patient's fibroblasts. It is possible that this might represent the metabolic abnormality.

Further observations on the treatment of infantile spasms with corticotropin

The results of corticotropin treatment of 33 subjects with infantile spasms are reported. In 8 patients the disease was idiopathic and in 25 secondary. Among the idiopathic cases, full clinical and EEG normalization was obtained in 5. No anticonvulsants were given after the corticotropin treatment. All children have remained normal without therapy. Among the 25 secondary cases, complete normalization was obtained in one with meningioma and improvement in 15 others. The dosage of ACTH was usually 2 U/Kg/bw for 10 days and 10 U/Kg/bw on alternate days for a further 20 days. These findings indicate that therapeutic results quite similar to the most favourable reported in the literature can be obtained, with few side effects, with a low dosage and a short period of treatment with corticotropin.