Multiple linked mouse chromosome 7 loci influence body fat mass.

BACKGROUND: Congenic mouse strains contain donor mouse strain DNA in genomes otherwise identical to a background strain. They can be used to identify defined chromosomal regions containing obesity genes with small effects. OBJECTIVE: : The objective of this study was to discover congenic strains containing genes that influence body fat in mice and to examine interactions between these genes. DESIGN: A survey of congenic strains showed that the B6.C-Tyr(c) H1(b) Hbb(d)/By (B6.C-H1) congenic strain, with a 24 centiMorgan (cM) donor region from strain BALB/cBy on chromosome 7, had 50% less fat than background C57BL/6By (B6By) mice. The congenic donor region was then divided into 11 smaller overlapping subcongenic regions. Genotype effects on obesity traits in the subcongenics were determined by breeding heterozygotes for each line and comparing phenotypes of littermates with different donor genotypes. RESULTS: At least three subcongenic strains, two with overlapping donor regions and one with a nonoverlapping donor strain region, were found to exhibit significant influences of donor region genotype on obesity. A cross of the two overlapping subcongenics demonstrated that a single gene in the overlap region could not account for the observed obesity effects. We also observed significant obesity differences between genetically identical progeny that were contingent on the genotype of their subcongenic mothers. CONCLUSIONS: These results demonstrate the existence of at least three genes influencing obesity in three subcongenic strains with donor strain chromosomal regions whose size ranges from 0.5 to 5 cM. A maternal effect gene influencing obesity may be present in some subcongenic strains.

Studies of natural allele effects in mice can be used to identify genes causing common human obesity.

Although genes causing rare Mendelian forms of human obesity have provided much useful information about underlying causes of obesity, these genes do not explain significant proportions of common obesity. This review presents evidence that animal models can be used to uncover subtle genetic effects on obesity and can provide a powerful rigorous compliment to human association studies. We discuss the advantages of animal models of obesity, various approaches to discovering obesity genes, and the future of mapping and isolating naturally occurring alleles of obesity genes. We review evidence that it is important to map naturally occurring obesity genes using quantitative trait locus (QTL) mapping, instead of mutagenesis and knockout models because the latter do not allow study of interactions and because naturally occurring obesity alleles can interfere with cloning from mutagenesis projects. Because a substantial percentage of human obesity results from complex interactions, the underlying genes can only be identified by direct studies in humans, which are still very difficult, or by studies in mice that begin with QTL mapping. Finally, we emphasize that animal model studies can be used to prove that a specific gene, only associated with obesity in humans, can indeed be the underlying cause of obesity in mammals.

Paternal UPD15: further genetic and clinical studies in four Angelman syndrome patients.

Among 25 patients diagnosed with Angelman syndrome, we detected 21 with deletion and 4 with paternal uniparental disomy (UPD), 2 isodisomies originating by postzygotic error, and 1 MII nondisjunction event. The diagnosis was obtained by molecular techniques, including methylation pattern analysis of exon 1 of SNRPN and microsatellite analysis of loci within and outside the 15q11-q13 region. Most manifestations present in deletion patients are those previously reported. Comparing the clinical data from our and published UPD patients with those with deletions we observed the following: the age of diagnosis is higher in UPD group (average 7 3/12 years), microcephaly is more frequent among deletion patients, UPD children start walking earlier (average age 2 9/12 years), whereas in deletion patients the average is 4 (1/2) years, epilepsy started later in UPD patients (average 5 10/12 years) than in deletion patients (average 1 11/12 years), weight above the 75th centile is reported mainly in UPD patients, complete absence of speech is more common in the deleted (88.9%) than in the UPD patients because half of the children are able to say few words. Thus, besides the abnormalities already described, the UPD patients have somewhat better verbal development, a weight above the 75th centile, and OFC in the upper normal range.

Associations between uncoupling protein 2, body composition, and resting energy expenditure in lean and obese African American, white, and Asian children.

BACKGROUND: Little is known about genes that affect childhood body weight. OBJECTIVE: The objective of this study was to examine the association between alleles of the mitochondrial uncoupling protein 2 (UCP2) gene and obesity because UCP2 may influence energy expenditure. DESIGN: We related UCP2 genotype to body composition and resting energy expenditure in 105 children aged 6-10 y. Overweight children and nonoverweight children of overweight parents were genotyped for a 45-base pair deletion/insertion (del/ins) in 3'-untranslated region of exon 8 and for an exon 4 C to T transition. RESULTS: Eighty-nine children were genotyped for the exon 8 allele: 50 children had del/del, 33 had del/ins, and 6 had ins/ins. Mean (+/-SD) body mass index (BMI; in kg/m(2)) was greater for children with del/ins (24.1 +/- 5.9) than for children with del/del (20.4 +/- 4.8; P < 0.001). BMI of ins/ins children (23.7 +/- 7.8) was not significantly different from that of del/ins children. A greater BMI in del/ins children was independent of race and sex. Body composition was also different according to UCP2 genotype. All body circumferences and skinfold thicknesses examined were significantly greater in del/ins than in del/del children. Body fat mass as determined by dual-energy X-ray absorptiometry was also greater in del/ins than in del/del children (P < 0.005). For 104 children genotyped at exon 4, no significant differences in BMI or body composition were found among the 3 exon 4 genotypes. Neither resting energy expenditure nor respiratory quotient were different according to UCP2 exon 4 or exon 8 genotype. CONCLUSIONS: The exon 8 ins/del polymorphism of UCP2 appears to be associated with childhood-onset obesity. The UCP2/UCP3 genetic locus may play a role in childhood body weight.

Heterogeneity of classic congenital muscular dystrophy with involvement of the central nervous system: report of five atypical cases.

A heterogeneous group of patients with congenital muscular dystrophy associated with clinical or radiologic central nervous system involvement other than the severe classic form with merosin deficiency, muscle-eye-brain disease, and Walker-Warburg syndrome is described. A probable hereditary or familial occurrence could be suggested in all patients. One merosin-positive patient presented severe motor incapacity and cerebral atrophy without any clinical manifestation of central nervous system involvement. A second patient, also merosin-positive, had moderate motor and mental handicap, and epilepsy with no changes in neuroimaging. A third patient, found to have partial merosin deficiency by muscle biopsy, manifested severe psychomotor retardation and cerebral atrophy with foci of abnormal white-matter signal on magnetic resonance imaging. Finally, two merosin-positive siblings with microcephaly, mental retardation, and an incapacitating progressive neuromuscular course, exhibited cataracts without defects of neuronal migration or brain malformation. This report emphasizes the broad clinical spectrum and heterogeneity of merosin-positive congenital muscular dystrophy with associated central nervous system involvement, and illustrates the importance of further studies on clinical, immunohistochemical, and genetic grounds for identifying new subsets of congenital muscular dystrophy.

A pilot study of topiramate in children with Lennox-Gastaut syndrome.

We conducted an open, add-on study with topiramate (TPM) as adjunctive therapy in Lennox-Gastaut syndrome (LGS), to assess the long-term efficacy and safety and to evaluate quality of life (QL) measurements in the chronic use of TPM. We studied 19 patients (11 male; age ranging from 4 to 14 years) with uncontrolled seizures receiving 2-3 anti-epileptic drugs. Patients were followed up to 36 months of treatment. A questionnaire was used to query parents about QL. Seven patients completed the study at 36 months and seizure frequency was reduced > or = 75% in 4, and < 50% in 3 patients. Two children became seizure free for more than 24 months. Most side effects were CNS related, with the most frequent being somnolence and anorexia. These were generally transient. One patient dropped-out due to powder in the urine. None of the patients required hospitalization. At 36 months, patients' alertness (2/7), interaction with environment (5/7), ability to perform daily activities (5/7), and verbal performance (6/7) improved on TPM. We conclude that TPM may be useful as adjunctive therapy in the treatment of LGS. The efficacy of TPM was maintained in long-term treatment in more than 40% of patients, long term safety was confirmed and QL improved on TPM.

Subacute sclerosing panencephalitis. Clinical aspects and prognosis. The Brazilian registry.

Subacute sclerosing panencephalitis (SSPE) is an inflammatory neurodegenerative disease related to the persistence of measles virus. Although its frequency is declining because of measles eradication, we still have some cases being diagnosed. With the aim to describe epidemiological aspects of SSPE in Brazil, we sent a protocol to Child Neurologists around the country, 48 patients were registered, 27 (56%) were from the southeast region, 34 (71%) were male and 35 (73%) white, 27 (56%) had measles, 9 (19%) had measles and were also immunized, 7 (14%) received only immunization, 1 patient had a probable neonatal form. Mean time between first symptoms and diagnosis was 12 months (22 started with myoclonus or tonic-clonic seizures, 7 (14%) with behavioral disturbances); 36 patients (75%) had EEG with pseudoperiodic complexes. Follow up performed in 28 (58%) patients showed: 12 died, 2 had complete remission and the others had variable neurological disability. Our data shows endemic regions in the country, a high incidence of post-immunization SSPE and a delay between first symptom and diagnosis.

Merosin-positive congenital muscular dystrophy in two siblings with cataract and slight mental retardation.

We report on two siblings that have been followed for 14 years, with merosin-positive congenital muscular dystrophy (CMD), cataract, retinitis pigmentosa, dysversion of the optic disc, but no cerebral anomalies, except for microcephaly and slight mental retardation (MR). The younger child had three generalized seizures easily controlled by anticonvulsant therapy. Both children presented hypotonia from birth, delayed psychomotor development, generalized muscular weakness, and atrophy and joint contractures of knees and ankles. The course of the disease, apparently static during the first 10 years of life, became progressive during the second decade with loss of deambulation by the age of 13. Creatine kinase was increased in both children. Bilateral cataract was diagnosed at 6-months of age. In spite of the occurrence of microcephaly, MR was slight and the siblings acquired reading and writing skills after the aged 10. Head magnetic resonance imaging showed normal results in both siblings. The classification of these cases within the broad spectrum of CMD is difficult since most of the known muscle-eye-brain syndromes generally show severe MR and brain anomalies. We consider these cases as corresponding to the rarer syndromes of merosin-positive CMD with associated features such as cataract and MR that were particularly emphasized during the 50th ENMC International Workshop on CMD [Dubowitz V. Workshop report: 50th ENMC International workshop on congenital muscular dystrophy. Neuromusc Disord 1997;7:539-547]. Further genetic, pathological, neuroradiological, and immunocytochemical studies will be necessary for better elucidation of the classification and pathogenesis of CMD.

Migraine in childhood and adolescence. A critical study of the diagnostic criteria and of the influence of age on clinical findings.

We studied 253 children aged <15 years. Phase 1 included 193 children with migraine (1.1 and 1.2) divided into two groups (<10 and > or = 10 years). We studied the relationship between age and migraine type, headache characteristics, and associated symptoms of the International Headache Society (IHS) definition. A higher frequency of migraine with aura, pulsatile quality, and unilateral location was observed in older children. In phase 2 we studied 176 children with headache (excluding migraine with aura), comparing diagnostic criteria, definition items, sensitivity, and specificity. The results showed that item B of the definition was the most frequent cause of exclusion in the 1.7 diagnostic group. Compared with Vahlquist and the IHS, the Prensky criteria were the most sensitive. Sensitivity was >70% for pain of moderate/severe intensity, duration between 2 and 48 h, isolated photophobia, isolated phonophobia, and aggravation with physical activity. Specificity was >70% for nausea, vomiting, phonophobia and photophobia, isolated photophobia, aggravation with physical activity, and isolated phonophobia. Based on three alternative definitions, each modifying one item of the IHS definition, the sensitivity and specificity of these alternative definitions were compared with the "extended" criteria (children with migraine without aura and migrainous disturbance, according to the IHS criteria, grouped together). Exclusion of headache duration increased sensitivity by 10%, compared to restrictive IHS criteria, without decreasing specificity.

[Angelman syndrome: a frequently undiagnosed cause of mental retardation and epilepsy. Case report]. / Síndrome de Angelman. Causa frequentemente não reconhecida de deficiência mental e epilepsia. Relato de caso.

The authors describe the case of a typical Angelman syndrome patient. The proband presents developmental delay, mental retardation, macrostomia, wide-spaced teeth, seizures, absent speech, jerky gait, and paroxysms of laughter. The cytogenetic and molecular studies showed a maternal deletion of 15q11q13. These results are in agreement with the clinical diagnosis of Angelman syndrome.

Treatment of febrile seizures with intermittent clobazam.

Fifty children, 24 female and 26 male, with ages varying from 6 to 72 months (mean = 23.7 m.) that experienced at least one febrile seizure (FS) entered a prospective study of intermittent therapy with clobazam. Cases with severe neurological abnormalities, progressive neurological disease, afebrile seizures, symptomatic seizures of other nature, or seizures during a central nervous system infection were excluded. Seizures were of the simple type in 25 patients, complex in 20 and unclassified in 5. The mean follow-up period was 7.9 months (range = 1 to 23 m.), and the age at the first seizure varied from 5 to 42 months (mean = 16.8 m.). Clobazam was administered orally during the febrile episode according to the child's weight: up to 5 kg, 5 mg/day; from 5 to 10 kg, 10 mg/day; from 11 to 15 kg, 15 mg/day, and over 15 kg, 20 mg/day. There were 219 febrile episodes, with temperature above 37.8 degrees C, in 40 children during the study period. Twelve children never received clobazam and 28 received the drug at least once. Drug efficacy was measured by comparing FS recurrence in the febrile episodes that were treated with clobazam with those in which only antipyretic measures were taken. Ten children (20%) experienced a FS during the study period. Of the 171 febrile episodes treated with clobazam there were only 3 recurrences (1.7%), while of the 48 episodes treated only with antipyretic measures there were 11 recurrences (22.9%), a difference highly significant (p < 0.0001). Adverse effects occurred in 10/28 patients (35.7%), consisting mainly in vomiting, somnolence and hyperactivity. Only one patient had recurrent vomiting which lead to drug interruption. These effects did not necessarily occurred in every instance the drug was administered, being present in one febrile episode and not in the others. We conclude that clonazepam is safe and efficacious in preventing FS recurrence. It may be an alternative to diazepam in the intermittent treatment of FS recurrence.

[Continuous spike-wave activity during sleep. Electroencephalographic and clinical features]. / Espícula-onda contínua durante o sono. Aspectos clínicos e eletrencefalográficos.

Seventeen children were retrospectively evaluated. They exhibited continuous spike-wave activity during slow wave sleep (CSWS). Five of these had only speech problems and seizures (Landau-Kleffner syndrome) (group 1). The other cases had developmental milestones acquisition delay and/or mental retardation (group 2). Epileptic seizures were present in 11 of these, tetraparesis was observed in 5, hemiparesis in 2, microcephaly in 2 and behavior disturbances in 4 cases. The electroencephalogram showed in all cases diffuse CSWS. Group 1 showed diffuse activity, at times accentuated in the centrotemporal region (4/5). Group 2 had widespread discharges, including multifocal activity (5/12), sometimes with anterior predominance (7/12). We concluded that CSWS is a non specific electrographic pattern observed in some types of epilepsy in childhood that have different clinical presentation. It has however some topographic differentiation, depending upon the lesional sites.

Vigabatrin in refractory childhood epilepsy. The Brazilian Multicenter Study.

Children, 47, with various types of severe drug-resistant epilepsy were entered into a prospective, add-on, open trial with vigabatrin. Patients with West syndrome and idiopathic generalized epilepsies were excluded. Seven children had the drug withdrawn, five because of increase in seizure frequency and two because of adverse effects. Drug efficacy, measured according to seizure type, showed a 100% decrease in seizure frequency in 18.6% of partial seizures and 17.3% of the generalized seizures. There was a higher than 50% decrease in 39.5% of partial and 60.8% of generalized seizures, and less than 50% decrease or increase in seizure frequency in 41.8% and 21.8% of partial and generalized seizures, respectively. Vigabatrin mean dosage during phase 3 was 63.6 mg/kg per day (S.D. = 30.5), ranging from 19.3 to 110.5 mg/kg per day. Parametric statistical analysis (Student's t-test) of seizure frequency between phases 1 and 3 showed a significant decrease in seizure frequency for partial (P = 0.022), and generalized seizures (P < 0.0001). Drug-related adverse effects were observed in 18/47 cases (38.3%), consisting mainly of irritability, hyperactivity, dizziness, somnolence and gastrointestinal symptoms.

Congenital muscular dystrophy with cerebral white matter hypodensity. Correlation of clinical features and merosin deficiency.

We report clinical and pathological findings in 9 children affected by congenital muscular dystrophy with normal or borderline intelligence and hypodensity of cerebral white matter (CMD-HWM), also frequently called 'occidental or western form of cerebro-muscular dystrophy' (OCMD). Our patients have uniform, distinct, clinical presentation that includes: normal or subnormal intelligence, severe, slowly progressive motor disability, high rate of facial involvement and dysmorphic aspect, increased creatine kinase levels and variable degrees of abnormal, radiographic, cerebral white matter pattern. By comparing our cases with previous reports we suggest that this subtype of CMD is not uncommon in Brazil and it is represented by a particularly severe and homogeneous clinical picture with important motor disability. The immunohistochemical staining for merosin, performed on the muscle biopsy of 6 among 9 patients, showed that all are merosin negative.

DOPA-sensitive progressive dystonia of childhood with diurnal fluctuations of symptoms: a case report.

Progressive dystonia with diurnal fluctuations sensitive to levodopa, also known as Segawa's disease, is a rare form of autosomal dominant extrapyramidal disease in the pediatric age group. The dystonic and Parkinson-like symptoms are the main clinical features of the disease and, characteristically but not in all cases, show a diurnal variation. They are absent or present to a lesser extent in the morning, worsening during the day. Treatment with small doses of levodopa results in remission or marked improvement of the symptomatology. We present the case of a 11 years old female patient that developed a dystonic posture in her feet that led her to a tip-toe walking pattern, since the age of 2. Diurnal fluctuations of the symptomatology were noticed by her mother. At 7 years of age she developed a left deviation of the head and an abnormal flexor posture of the left arm. In the next years the symptoms progressed and the fluctuations became less evident. At the age of 10, they were present soon after she woke up in the morning. The neurological examination disclosed a dystonic posturing of the head and left arm, a generalized rigidity of the extremities and a palpebral tremor. Laboratory examinations, including copper and ceruloplasmin, and neuro-imaging studies were negative. She was started on levodopa 150 mg/day with prompt disappearance of the symptomatology. After one-year follow-up she is symptom-free with only 100 mg/day of levodopa. No adverse effect was observed so far.

Hyperekplexia, a cause of neonatal apnea: a case report.

We report a case of non-familial hyperekplexia which characteristically developed apnea and feeding difficulties in the neonatal period. The abnormal startle response was evident from the second week of life onwards. The infant showed a marked improvement of the startle response and muscle hypertonia with clonazepam. Clobazam was also tried with no apparent response. A prominent long latency C response was observed on EMG examination, suggesting a possible cortical neuronal hyperexcitability origin for the abnormal startle response observed in hyperekplexia.

Autosomal recessive nondystrophic myotonia. Report of a case with unusual clinical course.

We describe the case of a girl with a probable autosomal recessive form of nondystrophic hereditary myotonia whose clinical findings are more compatible with the dominant ones mainly myotonia congenita of Thomsen or myotonia fluctuans. Besides the clinical aspects of the atypical form presented by our patient, the efficacy of the more available drugs employed for the treatment of myotonia congenita is briefly discussed.

Pediatric multiple sclerosis report of 14 cases.

We present clinical data from 14 multiple sclerosis (MS) patients who have been admitted to our hospital between January 1980 and May 1992, whose age of onset ranged from 2-15 years. Our patients could be classified as having a clinically definite form of the disease. Initial symptoms varied from minor, such as motor or sensory impairment, bladder dysfunction, to the worst clinical presentation, suggesting diffuse encephalopathy. All the patients had a relapsing-remitting course. We report the paraclinical and laboratory examinations that were done in these patients. Over the period 1980 to 1992 these patients had 39 attacks. CSF analysis was performed in the phase of activity of the disease on 23 occasions and was normal in 12. At least one brain CT scan was performed in 9 patients and showed white matter abnormalities in 6. Cranial magnetic resonance imaging was done in 6 patients and were abnormal in 5. Visual evoked potential (EP) was abnormal in 7 of 8 patients; brainstem acoustic EP was abnormal in 4 of 8 patients and somatosensory EP in 4 of 8. MS is not so rare in childhood and although its diagnosis is essentially a clinical one, paraclinical investigations are of great value in the identification of demyelinating disorders in childhood.

[Myotonic dystrophy: study of clinico-genetic correlation in a pair of relatives (father-son)]. / Distrofia miotônica. Estudo da correlação clínico-genética em um par familiar (pai-filho).

We report the case of a child with myotonic dystrophy (DM) with symptoms beginning at the age of seven, whose genetic study showed an additional DNA fragment, greater than of his father, an asymptomatic carrier. The clinical and molecular analysis of this parent-child pair are probably the first described in Brazil, since the recent discovery of genetic abnormality in DM by American and European researchers, that explained the long-debated phenomenon of "anticipation" in this disease. The main advances in molecular genetics in DM and its correlation with increasing severity and earlier onset of the symptoms in successive generations of a family are commented briefly.