Spino-cerebellar degeneration with polyneuropathy associated with ceroid lipofuscinosis in one family

Orphan Peripheral Neuropathies

Objectives:

Generally, neuropathies of peripheral nerves are a frequent condition (prevalence 2–3%) and most frequently due to alcoholism, diabetes, renal insufficiency, malignancy, toxins, or drugs. However, the vast majority of neuropathies has orphan status. This review focuses on the etiology, frequency, diagnosis, and treatment of orphan neuropathies.

Methods:

Literature review

Results:

Rareness of diseases is not uniformly defined but in the US an orphan disease is diagnosed if the prevalence is <1:200000, in Europe if <5:10000. Most acquired and hereditary neuropathies are orphan diseases. Often the causative variant has been reported only in a single patient or family, particularly the ones that are newly detected (e.g. SEPT9, SORD). Among the complex neuropathies (hereditary multisystem disorders with concomitant neuropathies) orphan forms have been reported among mitochondrial disorders (e.g. NARP, MNGIE, SANDO), spinocerebellar ataxias (e.g. TMEM240), hereditary spastic paraplegias (e.g UBAP1), lysosomal storage disease (e.g. Schindler disease), peroxisomal disorders, porphyrias, and other types (e.g. giant axonal neuropathy, Tangier disease). Orphan acquired neuropathies include the metabolic neuropathies (e.g. vitamin-B1, folic acid), toxic neuropathies (e.g. copper, lithium, lead, arsenic, thallium, mercury), infectious neuropathies, immune-mediated (e.g. Bruns-Garland syndrome), and neoplastic/paraneoplastic neuropathies.

Conclusions:

Though orphan neuropathies are rare per definition they constitute the majority of neuropathies and should be considered as some of them are easy to identify and potentially treatable, as clarification of the underlying cause may contribute to the knowledge about etiology and pathophysiology of these conditions, and as the true prevalence may become obvious only if all ever diagnosed cases are reported.

Altered carbon dioxide metabolism and creatine abnormalities in rett syndrome

Despite their good appetite, many females with Rett syndrome (RTT) meet the criteria for moderate to severe malnutrition. Although feeding difficulties may play a part in this, other constitutional factors such as altered metabolic processes are suspected. Irregular breathing is a common clinical feature, leading to chronic respiratory alkalosis or acidosis. We assumed that these changes in intracellular pH cause disturbances in the metabolic equilibrium, with important nutritional consequences. The study population consisted of a group of thirteen well-defined RTT girls with extended clinical, molecular and neurophysiological assessments. Despite normal levels of total dietary energy and protein intakes, malnutrition was confirmed based on significantly low fat-free mass index (FFMI) values. Biochemical screening of multiple metabolic pathways showed significantly elevated plasma creatine concentrations and increased urinary creatine/creatinine ratio in five RTT girls. Four girls, 10 years and older, were forceful breathers, one 13-year-old girl had an undetermined cardiorespiratory phenotype. An isolated increase of the urinary creatine/creatinine ratio was seen in two girls, a 9-year old forceful and a 4-year old feeble breather. Given that the young girls are feeble breathers and the older girls are forceful breathers, it is impossible to determine whether the elevated creatine concentrations are due to increasing age or cardiorespiratory phenotype. Furthermore, MeCP2 deficiency may cause epigenetic aberrations affecting the expression of the creatine-transporter gene, which is located at Xq28. Further studies are required to confirm these findings and to provide greater insight into the pathogenesis of the abnormal creatine metabolism in RTT.

Improvement in motor and exploratory behavior in Rett syndrome mice with restricted ketogenic and standard diets

Rett syndrome (RTT) is a rare X-linked autistic-spectrum neurological disorder associated with impaired energy metabolism, seizure susceptibility, progressive social behavioral regression, and motor impairment primarily in young girls. The objective of this study was to examine the influence of restricted diets, including a ketogenic diet (KD) and a standard rodent chow diet (SD), on behavior in male Mecp2(308/y) mice, a model of RTT. The KD is a high-fat, low-carbohydrate diet that has anticonvulsant efficacy in children with intractable epilepsy and may be therapeutic in children with RTT. Following an 11-day pretrial period, adult wild-type and mutant Rett mice were separated into groups that were fed either an SD in unrestricted or restricted amounts or a ketogenic diet (KetoCal) in restricted amounts for a total of 30 days. The restricted diets were administered to reduce mouse body weight by 20-23% compared to the body weight of each mouse before the initiation of the diet. All mice were subjected to a battery of behavioral tests to determine the influence of the diet on the RTT phenotype. We found that performance in tests of motor behavior and anxiety was significantly worse in male RTT mice compared to wild-type mice and that restriction of either the KD or the SD improved motor behavior and reduced anxiety. We conclude that although both restricted diets increased the tendency of Rett mice to explore a novel environment, the beneficial effects of the KD were due more to calorie restriction than to the composition of the diet. Our findings suggest that calorically restricted diets could be effective in reducing the anxiety and in improving motor behavior in girls with RTT.

Genetics of epilepsy: current status and perspectives

Epilepsy affects more than 0.5% of the world's population and has a large genetic component. The most common human genetic epilepsies display a complex pattern of inheritance and the susceptibility genes are largely unknown. However, major advances have recently been made in our understanding of the genetic basis of monogenic inherited epilepsies. Progress has been particularly evident in familial idiopathic epilepsies and in many inherited symptomatic epilepsies, with the discovery that mutations in ion channel subunits are implicated, and direct molecular diagnosis of some phenotypes of epilepsy is now possible. This article reviews recent progress made in molecular genetics of epilepsy, focusing mostly on idiopathic epilepsy, and some types of myoclonus epilepsies. Mutations in the neuronal nicotinic acetylcholine receptor alpha4 and beta2 subunit genes have been detected in families with autosomal dominant nocturnal frontal lobe epilepsy, and those of two K(+) channel genes were identified to be responsible for underlying genetic abnormalities of benign familial neonatal convulsions. The voltage-gated Na(+) -channel (alpha1,2 and beta1 subunit), and GABA receptor (gamma2 subunit) may be involved in the pathogenesis of generalized epilepsy with febrile seizure plus and severe myoclonic epilepsy in infancy. Mutations of Ca(2+)-channel can cause some forms of juvenile myoclonic epilepsy and idiopathic generalized epilepsy. Based upon these findings, pathogenesis of epilepsy as a channelopathy and perspectives of molecular study of epilepsy are discussed.

A case of late infantile neuronal ceroid lipofuscinosis associated with precocious puberty

Neuronal ceroid lipofuscinosis is one of the hereoffegenerative diseases for which clinical and neuropathologic findings are well documented. We present a patient with late infantile neuronal ceroid lipofuscinosis with true precocious puberty; to our knowledge, this association has not been reported before. The association could be due to an underlying disturbance of hypothalamic-pituitary gonadal function, or to coincidence.

Oropharyngeal dysfunction and gastroesophageal dysmotility are present in girls and women with Rett syndrome

BACKGROUND

Feeding impairment frequently complicates the course of children with neurologic disorders and places them at risk for malnutrition and growth failure. Although feeding abnormalities have been reported in female patients with Rett syndrome, the mechanisms that account for these findings have not been elucidated fully. This study was designed to characterize the clinical features of oropharyngeal and gastroesophageal dysfunction and their impact on the dietary intake and nutritional status of female subjects with Rett syndrome.

METHODS

The clinical features of oropharyngeal and gastroesophageal dysfunction in 13 female patients with Rett syndrome, (age range, 3.7 to 25.7 years) were characterized by an oral feeding assessment, swallowing function study, and upper gastrointestinal series. Growth, nutritional status, and body composition were determined by stadiometry and anthropometry. Dietary intakes were determined from 3-day food records.

RESULTS

Oropharyngeal dysfunction and gastroesophageal dysmotility were present in 100% and 69%, respectively, of the study patients with Rett syndrome. The scope and severity of these abnormalities were apparent only by videofluoroscopy. Abnormalities of oropharyngeal function included poor tongue mobility, reduced oropharyngeal clearance, and laryngeal penetration of liquids and solid food during swallowing. Esophageal dysmotility included absent primary or secondary waves, delayed emptying, atony, the presence of tertiary waves, spasm, and gastroesophageal reflux. Gastric dysmotility included diminished peristalsis or atony. Lower dietary energy intakes were associated with persistence of residue in the valleculae and pyriform sinuses and less body fat.

CONCLUSION

The prevalence of oropharyngeal dysfunction and gastroesophageal dysmotility warrants early diagnostic evaluation and intervention strategies to improve the nutritional status of girls and women with RS.

Vitamin E serum levels in Rett syndrome

In order to study the role of vitamin E in the pathogenesis of Rett syndrome (RS), we analysed vitamin E serum levels in twenty-eight patients affected by this disorder. We found lower vitamin E serum levels in nine cases (32.1%). These results indicated that the oxidative free radical metabolism may be impaired in a significant percentage of Rett syndrome patients suggesting the need for further studies of tissue vitamin E in different brain regions.

Increased energy expenditure associated with repetitive involuntary movement does not contribute to growth failure in girls with Rett syndrome

OBJECTIVE

To determine whether increased total daily energy expenditure (TDEE) associated with repetitive, involuntary movements contributes to growth failure in girls with Rett syndrome (RS).

STUDY DESIGN

Fourteen girls with RS and 11 healthy girls were studied for 10 days to obtain measurements of height, weight, body circumference, and skin-fold thickness with stadiometric and anthropometric methods; whole-body potassium by potassium 40 counting; 72-hour dietary energy intakes by test weighing; 24-hour activity patterns using observational methods; and TDEE using the doubly-labeled water technique.

RESULTS

TDEE, when adjusted for differences in lean body mass, did not differ significantly between girls with RS and healthy girls. Although girls with RS spent more waking hours in physical activity than their healthy counterparts (85%+/-10% vs. 73%+/-11% awake time per day, p < 0.05), their repetitive movements were not sufficiently intense to increase TDEE. However, girls with RS had significantly less lean body mass, but not body fat, which contributed to their lower absolute TDEE in comparison with that of healthy girls (845+/-251 vs. 1453+/-534 kcal/day, p < 0.01). Dietary energy intake, when adjusted for differences in body weight, was not significantly different in girls with RS compared with healthy girls.

CONCLUSIONS

Increased TDEE as a result of repetitive, involuntary movements does not explain the alterations in growth and body composition of girls with RS.

Familial spastic paraplegia, axonal sensory-motor polyneuropathy and bulbar amyotrophy with facial dysmorphia: new cases of Troyer-like syndrome

We studied two Libyan siblings, born to healthy consanguineous parents, who had suffered from a progressive neurological disorder, characterized by facial dysmorphia, ataxia, spastic paraplegia and an axonal sensory-motor polyneuropathy, since the age of 3 years. The clinical picture progressed slowly over a 6-year period to involve also bulbar and distal limb muscles. Interestingly, we found unusual tubulofilamentous inclusions in peripheral nerves and presynaptic buttons at the neuromuscular junctions. Describing the clinical picture of this presumably new disorder, we comment on the difference from similar conditions.

Studies of atypical JNCL suggest overlapping with other NCL forms

In the United States, juvenile neuronal ceroid-lipofuscinosis (JNCL) is the most common form of NCL. This study analyzed 191 cases, diagnosed on the basis of age-at-onset, clinical symptomatology, and pathologic findings. Twenty percent (40/191) of these cases from 24/120 families manifested atypical clinical symptomatology and/or pathologic findings (typical revealed fingerprints and atypical revealed mixed inclusions, or only curvilinear or granular profiles) and, therefore, represent variant forms of JNCL. Those patients in the study with typical JNCL were a uniform group of cases, whereas the atypical were heterogenous and were divided into 8 subgroups based on the clinicopathologic findings. Forty-three families were analyzed (27 typical, 16 atypical) for the common 1.02 kb deletion and several pedigrees for novel mutations. In typical JNCL the common 1.02 kb deletion in both alleles (homozygous) were observed in 23/27, and only 1 allele (heterozygous) was exhibited in 4/27 families. In atypical JNCL families, 5/16 were heterozygous for the common 1.02 kb deletion. None of the remaining 11/16 families had the common 1.02 kb deletion in either allele, but in 9/11 cases the palmitoyl-protein thioesterase (PPT) levels were deficient. In cases where the mutation in CLN3 gene has not been identified, several possibilities may exist. The phenotype may be caused by a yet undefined mutation in CLN3 or may be due to overlapping with other forms of NCL.

[Peripheral neuropathies in childhood: a neuropathological approach]

Peripheral neuropathies affect children more often than the young and middle age adults, but less frequently than the elderly. They differ from those in the adults because of the high incidence of hereditary neuropathies, including those associated with metabolic and degenerative disorders of the central nervous system; the low incidence of toxic neuropathies and those associated with systemic disorders; and a lower incidence of chronic acquire polineuropathies. Nerve biopsies are indicated if the diagnosis has not been made with clinical and electrophysiologic studies and other methods, and should only be performed in laboratories with appropriated techniques for the study of the nerve. It is important to know the normal development of the nerve, the thickness of the myelin sheath and the distribution of small and large fibers, according to the age. The main morphological aspects of the most frequent neuropathies in children--acquired (inflammatory, demyelinating) and hereditary (sensory-motor, sensory-autonomic, ataxic, and those associated with metabolic and degenerative disorders), are reviewed.

Classification of the neuronal ceroid-lipofuscinoses: expansion of the atypical forms

The neuronal ceroid-lipofuscinoses (NCL) are a group of different genetic diseases. The major types of NCL are expressed by six forms which represent different clinicopathologic and genetic forms. These are CLN-1, Infantile; CLN-2, Late Infantile; CLN-3, Juvenile; CLN-4, Adult-Recessive; CLN-5, Adult-Dominant; and CLN-6, Early Juvenile. The distinction between CLN-4 and CLN-5 is still disputatious. CLN-6 has been called CLN-5. A seventh classification of NCL represents from 12 to 20% of those afflicted. This group consists of an extensive array of atypical types of ceroid-lipofuscin accumulation in the secondary lysosomes of neurons and cells of other tissues (e.g., skin, conjunctiva, and lymphocytes) or by presumed clinical and genetic relationships. The authors have identified 15 atypical subtypes of NCL. These as a group are here described as a seventh form. Further biochemical, molecular, and genetic studies will identify more precisely the phenotypic and genotypic expression of these "minor" forms of NCL.

Neuronal ceroid-lipofuscinoses: the current status

In view of the epidemiological connotation of childhood neuronal ceroid-lipofuscinosis (NCL) as one of the most frequent progressive lysosomal diseases and neurodegenerative disorders in children, the recognition of the individual clinical forms of childhood NCL is still based on invasive diagnostic electronmicroscopy which, currently, may be applied also for prenatal diagnosis. Like other inherited disorders, the NCL group has finally also benefited from the genetic breakthroughs of localization of the genes for infantile NCL and juvenile NCL on chromosomes 1 and 16, respectively. This review concerns recent advances in morphological studies, broadening of the clinical spectrum of childhood NCL, new biochemical findings, and preliminary therapeutic results. Hereditary animal models, largely for human juvenile NCL, have been successfully employed in elucidation of the nosology of NCL, but the basic defect in human, canine and ovine NCL remains unknown.

Lectin histochemistry in brains with juvenile form of neuronal ceroid-lipofuscinosis (Batten disease)

Defective utilization of dolichols in the synthesis of glycoprotein leads to an accumulation of the storage, pigment "ceroid" lipofuscin, containing high-mannose-type glycoconjugates, in brains affected by neuronal ceroid-lipofuscinoses (NCL). We have employed lectin histochemistry to study the distribution of such compounds and the composition of other glycoconjugates in brains of patients with a juvenile form of the disease (JNCL). Concanavalin A detected the high-mannose glycoconjugates in all neurons of brains with JNCL, in lipofuscin-containing neurons of aging brains and in some neurons of age-matched control brains. Three other lectins (soybean agglutinin, Peanut agglutinin and Ulex europaeus agglutinin-I) recognized sugar moieties in neurons containing lipofuscin in patients only with JNCL and not in age-matched or aging brains. The results led to the conclusion, that the binding pattern of these three lectins may differentiate between storage materials of NCL and aging brains.

Topographic heterogeneity of amyloid B-protein epitopes in brains with various forms of neuronal ceroid lipofuscinoses suggesting defective processing of amyloid precursor protein

To verify our hypothesis of defective protease inhibitor domains that are encoded by abnormal processing of amyloid precursor protein (APP) in brains of patients with neuronal ceroid lipofuscinoses (NCL), immunohistochemical and cytochemical studies were performed with monoclonal antibodies (mAbs) directed against various domains of APP. For the studies, 22 autopsy brains were used: 12 with different forms of NCL, and 10 control brains. The staining procedure for the avidin-biotin complex (ABC) technique and the postembedding gold-labelled procedure for electron microscopy (EM) were employed. Of all mAbs used for the study, only mAbs generated against amyloid B-protein bound to neural tissue were affected with NCL. The strongest immunostaining of neurons and of some reactive glial cells was found in brains with the juvenile form of NCL. Only in the infantile form of the disease were some neurons overloaded with storage material weakly immunoreactive. In brains of patients with the adult form of NCL, immunoreactivity was found in affected neurons and in extracellularly deposited material of senile plaques. The results of EM study showed that the immunoreactivity was restricted to lysosomal cytosomes in neural tissue with any form of NCL selectively localized on the curvilinear and fingerprint proteinaceous component of ceroid lipofuscin. Studies performed on control aging brains and Alzheimer's disease (AD) brains confirmed previous observations of immunoreactivity being found diffusely in the protein component of some neurons containing lipopigment.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinico-pathological variability in the childhood neuronal ceroid-lipofuscinoses and new observations on glycoprotein abnormalities

Our 86 cases of neuronal ceroid-lipofuscinosis (NCL) included 7 children with the infantile variant, 28 with the late infantile variant, and 51 with the juvenile variant. Thirty-one cases were drawn from a NCL registry and were not evaluated personally by the authors. Another 30 cases from the registry were not included because of inadequate data. The clinical course was subacute in most children with the infantile and late infantile variants and chronic in the juvenile variant. Sixteen of 86 cases (19%) were considered to be atypical clinically [3/7 (43%) with the infantile variant, 3/28 (11%) with the late infantile variant, and 10/51 (20%) with the juvenile variant]. Clinical variability among and between families was most striking in the juvenile variant. Pathological investigations of skin, buffy coat and/or brain showed atypical and/or more than one type of cytoplasmic inclusions in 10/50 (20%) of late infantile and juvenile variants. All of the children with the infantile variant had granular, osmiophilic profile in tissues. Biochemical studies on the glycoproteins of cultured fibroblasts in three cases of juvenile NCL showed that there was a higher proportion of one size class of N-linked oligosaccharides and a higher proportion of mannose-containing glycoproteins in NCL than in control cells. This supports previous lectin histochemical studies of glycoconjugates in skin of juvenile NCL [Wisniewski and Szumanska, 1986] and suggests that there may be defects in the processing of N-linked oligosaccharides in the glycoproteins of juvenile NCL.