Neurodevelopmental status and adaptive behavior of pediatric patients with mucopolysaccharidosis II: a longitudinal observational study

BACKGROUND

Mucopolysaccharidosis (MPS) II is a rare, X-linked lysosomal storage disease. Approximately two-thirds of patients have central nervous system involvement with some demonstrating progressive cognitive impairment (neuronopathic disease). The natural history of cognitive and adaptive function in patients with MPS II is not well-defined. This 2-year, prospective, observational study evaluated the neurodevelopmental trajectories of boys with MPS II aged ≥ 2 years and < 18 years.

RESULTS

Overall, 55 patients were enrolled. At baseline, mean (standard deviation [SD]) age was 5.60 (3.32) years; all patients were receiving intravenous idursulfase. Cognitive and adaptive function were assessed using the Differential Ability Scales, Second Edition (DAS-II) General Conceptual Ability (GCA) and the Vineland Adaptive Behavior Scales, Second Edition (VABS-II) Adaptive Behavior Composite (ABC) scores, respectively. Baseline mean (SD) DAS-II GCA and VABS-II ABC scores were 78.4 (19.11) and 83.7 (14.22), respectively, indicating low cognitive function and moderately low adaptive behavior. Over 24 months, modest deteriorations in mean (SD) scores were observed for DAS-II GCA (-3.8 [12.7]) and VABS-II ABC (-2.0 [8.07]). Changes in DAS-II GCA scores varied considerably, and data suggested the existence of four potential patient subgroups: (1) patients with marked early impairment and rapid subsequent decline, (2) patients with marked early impairment then stabilization, (3) patients with mild early impairment then stabilization, and (4) patients without impairment who remained stable. Subgroup analyses revealed numerically greater DAS-II GCA score reductions from baseline in patients aged < 7 years at baseline (vs. those aged ≥ 7 years) and in patients with DAS-II GCA scores ≤ 70 at baseline (vs. those with scores > 70); between-group differences were nonsignificant. No clear subgroups or patterns were identified for individual changes in VABS-II ABC scores. In total, 49 patients (89.1%) reported ≥ 1 adverse event (AE) and nine patients (16.4%) reported serious AEs.

CONCLUSIONS

Some patients with MPS II had rapid declines in cognitive ability, whereas others remained relatively stable after an initial decline. These insights provide a basis for more detailed analyses of different patient subgroups, which may enhance the definition and understanding of factors that influence cognitive and adaptive function in MPS II.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT01822184. Registered retrospectively: April 2, 2013.

Intrathecal idursulfase-IT in patients with neuronopathic mucopolysaccharidosis II: Results from a phase 2/3 randomized study

Two-thirds of patients with mucopolysaccharidosis II (MPS II; Hunter syndrome) have cognitive impairment. This phase 2/3, randomized, controlled, open-label, multicenter study (NCT02055118) investigated the effects of intrathecally administered idursulfase-IT on cognitive function in patients with MPS II. Children older than 3 years with MPS II and mild-to-moderate cognitive impairment (assessed by Differential Ability Scales-II [DAS-II], General Conceptual Ability [GCA] score) who had tolerated intravenous idursulfase for at least 4 months were randomly assigned (2:1) to monthly idursulfase-IT 10 mg (n = 34) via an intrathecal drug delivery device (IDDD; or by lumbar puncture) or no idursulfase-IT treatment (n = 15) for 52 weeks. All patients continued to receive weekly intravenous idursulfase 0.5 mg/kg as standard of care. Of 49 randomized patients, 47 completed the study (two patients receiving idursulfase-IT discontinued). The primary endpoint (change from baseline in DAS-II GCA score at week 52 in a linear mixed-effects model for repeated measures analysis) was not met: although there was a smaller decrease in DAS-II GCA scores with idursulfase-IT than with no idursulfase-IT at week 52, this was not significant (least-squares mean treatment difference [95% confidence interval], 3.0 [-7.3, 13.3]; p = 0.5669). Changes from baseline in Vineland Adaptive Behavioral Scales-II Adaptive Behavior Composite scores at week 52 (key secondary endpoint) were similar in the idursulfase-IT (n = 31) and no idursulfase-IT (n = 14) groups. There were trends towards a potential positive effect of idursulfase-IT across DAS-II composite, cluster, and subtest scores, notably in patients younger than 6 years at baseline. In a post hoc analysis, there was a significant (p = 0.0174), clinically meaningful difference in change from baseline in DAS-II GCA scores at week 52 with idursulfase-IT (n = 13) versus no idursulfase-IT (n = 6) among those younger than 6 years with missense iduronate-2-sulfatase gene variants. Overall, idursulfase-IT reduced cerebrospinal glycosaminoglycan levels from baseline by 72.0% at week 52. Idursulfase-IT was generally well tolerated. These data suggest potential benefits of idursulfase-IT in the treatment of cognitive impairment in some patients with neuronopathic MPS II. After many years of extensive review and regulatory discussions, the data were found to be insufficient to meet the evidentiary standard to support regulatory filings.

Long-term open-label extension study of the safety and efficacy of intrathecal idursulfase-IT in patients with neuronopathic mucopolysaccharidosis II

Enzyme replacement therapy with weekly infused intravenous (IV) idursulfase is effective in treating somatic symptoms of mucopolysaccharidosis II (MPS II; Hunter syndrome). A formulation of idursulfase for intrathecal administration (idursulfase-IT) is under investigation for the treatment of neuronopathic MPS II. Here, we report 36-month data from the open-label extension (NCT02412787) of a phase 2/3, randomized, controlled study (HGT-HIT-094; NCT02055118) that assessed the safety and efficacy of monthly idursulfase-IT 10 mg in addition to weekly IV idursulfase on cognitive function in children older than 3 years with MPS II and mild-to-moderate cognitive impairment. Participants were also enrolled in this extension from a linked non-randomized sub-study of children younger than 3 years at the start of idursulfase-IT therapy. The extension safety population comprised 56 patients who received idursulfase-IT 10 mg once a month (or age-adjusted dose for sub-study patients) plus IV idursulfase (0.5 mg/kg) once a week. Idursulfase-IT was generally well tolerated over the cumulative treatment period of up to 36 months. Overall, 25.0% of patients had at least one adverse event (AE) related to idursulfase-IT; most treatment-emergent AEs were mild in severity. Of serious AEs (reported by 76.8% patients), none were considered related to idursulfase-IT treatment. There were no deaths or discontinuations owing to AEs. Secondary efficacy analyses (in patients younger than 6 years at phase 2/3 study baseline; n = 40) indicated a trend for improved Differential Ability Scale-II (DAS-II) General Conceptual Ability (GCA) scores in the early idursulfase-IT versus delayed idursulfase-IT group (treatment difference over 36 months from phase 2/3 study baseline: least-squares mean, 6.8 [90% confidence interval: -2.1, 15.8; p = 0.2064]). Post hoc analyses of DAS-II GCA scores by genotype revealed a clinically meaningful treatment effect in patients younger than 6 years with missense variants of the iduronate-2-sulfatase gene (IDS) (least-squares mean [standard error] treatment difference over 36 months, 12.3 [7.24]). These long-term data further suggest the benefits of idursulfase-IT in the treatment of neurocognitive dysfunction in some patients with MPS II. After many years of extensive review and regulatory discussions, the data were found to be insufficient to meet the evidentiary standard to support regulatory filings.

Fluctuation-induced current from freestanding graphene

At room temperature, micron-sized sheets of freestanding graphene are in constant motion, even in the presence of an applied bias voltage. We quantify the out-of-plane movement by collecting the displacement current using a nearby small-area metal electrode and present an Ito-Langevin model for the motion coupled to a circuit containing diodes. Numerical simulations show that the system reaches thermal equilibrium and the average rates of heat and work provided by stochastic thermodynamics tend quickly to zero. However, there is power dissipated by the load resistor, and its time average is exactly equal to the power supplied by the thermal bath. The exact power formula is similar to Nyquist's noise power formula, except that the rate of change of diode resistance significantly boosts the output power, and the movement of the graphene shifts the power spectrum to lower frequencies. We have calculated the equilibrium average of the power by asymptotic and numerical methods. Excellent agreement is found between experiment and theory.

Characterization and Outcomes of Epileptic Seizures in Mexican Pediatric Patients With Anti-N-Methyl-D-Aspartate Receptor Encephalitis

Introduction

Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is one of the most common autoimmune encephalitides. The frequency of anti-NMDAR encephalitis is known to exceed the frequency of any individual viral encephalitis in young subjects. Epileptic seizures are a cardinal symptom in anti-NMDAR encephalitis; a significant amount of pediatric patients exhibit seizures as the first symptom of the disease, and most of them will develop them during the acute phase. The use of antiepileptic drugs (AEDs) is a cornerstone of the treatment of these patients, but the choice of agent and duration of treatment is currently unknown.

Materials and methods

This was a single-center retrospective review case series of all pediatric patients with a confirmed diagnosis of anti-NMDAR encephalitis and epileptic seizures admitted to the National Institute of Pediatrics in Mexico City from January 2012 to July 2019.

Results

We included a total of 31 patients (males 64.5%, median age: 10 years). No patient showed evidence of teratoma; only 38% of cases had a viral prodrome. Most patients initially exhibited psychiatric symptoms (51%), but the leading cause in soliciting medical assistance was the presence of epileptic seizures (71%). About 85% of patients presented epileptic seizures during the course of the illness, predominantly focal onset seizures (42% focal to bilateral tonic-clonic seizures, 32% focal seizures with impaired awareness). Electroencephalogram (EEG) was abnormal in 97% of patients; the characteristic extreme delta brush pattern was found in 9% of patients. Two AEDs on average were required to control seizures during the acute stage. In six (19%) patients, human herpesvirus (HHV) was detected in cerebrospinal fluid (CSF); all of them had epileptic seizures, which were more resistant to pharmacological treatment during the acute phase, requiring a higher number of AED (median 2.5 vs. 2). The development of epilepsy after acute encephalitis was uncommon; at 24 months, only one patient continued to have epileptic seizures. One of the factors most closely related to the persistence of epileptic seizures was the inadequate response to immunotherapy after four weeks. The functional prognosis was generally good; at a two-year follow-up, only two (10%) patients had a significant disability [modified Rankin Scale (mRS) score: 3-5]; both patients had seizures at a one-year follow-up.

Conclusions

Sustained use of AEDs after the acute phase of anti-NMDAR encephalitis is controversial. We found that the continuation of AEDs after the acute phase could be considered in the following scenarios: status epilepticus (SE), inadequate response to immunotherapy at four weeks, and a high mRS score at discharge and during follow-up. In other cases, discontinuation of AED may be warranted. More studies are needed in our country to replicate these results.

Bifurcation analysis and phase diagram of a spin-string model with buckled states

We analyze a one-dimensional spin-string model, in which string oscillators are linearly coupled to their two nearest neighbors and to Ising spins representing internal degrees of freedom. String-spin coupling induces a long-range ferromagnetic interaction among spins that competes with a spin-spin antiferromagnetic coupling. As a consequence, the complex phase diagram of the system exhibits different flat rippled and buckled states, with first or second order transition lines between states. This complexity translates to the two-dimensional version of the model, whose numerical solution has been recently used to explain qualitatively the rippled to buckled transition observed in scanning tunneling microscopy experiments with suspended graphene sheets. Here we describe in detail the phase diagram of the simpler one-dimensional model and phase stability using bifurcation theory. This gives additional insight into the physical mechanisms underlying the different phases and the behavior observed in experiments.

[The prevalence of obesity and metabolic syndrome in paediatric patients with epilepsy treated in monotherapy with valproic acid]

INTRODUCTION

Valproic acid (VPA) is a useful antiepileptic drug for controlling different types of epilepsy. It has several side effects and is associated to increased body weight, as well as metabolic and endocrine disorders, including metabolic syndrome.

AIM

To determine the prevalence of obesity and metabolic syndrome among paediatric patients with epilepsy treated in monotherapy with VPA.

PATIENTS AND METHODS

The study was cross-sectional, observational and analytical. A sample of patients treated with VPA between 2010-2014 were studied and the body mass index (BMI), abdominal perimeter, arterial blood pressure, glucose, triglycerides and high density lipoproteins (HDL) were studied in search of obesity and metabolic syndrome. Obesity was defined as a BMI above the 95th percentile, and metabolic syndrome was considered if at least three of the following criteria were fulfilled: abdominal perimeter above the 90th percentile, systolic arterial pressure above the 90th percentile, triglycerides above 110 mg/dL and HDL below 40 mg/dL.

RESULTS

A total of 47 patients with a mean age of 10.1 ± 4 years were studied; 51.06% were males. Eight (17%) of them developed obesity and, of those, two (25%) had metabolic syndrome. Three patients went on to become overweight (6%). Statistically significant differences were observed in the mean age in comparison to the BMI groups, where the obese patients were adolescents (ANOVA, p = 0.0001) and those who took more VPA per day were the obese (ANOVA, p = 0.024).

CONCLUSIONS

Patients treated with VPA who become obese may go on to develop metabolic syndrome. They require careful monitoring and, if they are seen to put on weight, withdrawal of the drug should be considered.

Analysis of the genetic variability and structure of Ochlerotatus taeniorhynchus (Diptera: Culicidae) populations from the Colombian Atlantic coast on the basis of random amplified polymorphic DNA markers

Ochlerotatus taeniorhynchus (Diptera: Culicidae) is a mosquito, which is an efficient vector of the virus causing epidemic-epizootic Venezuelan equine encephalitis in Colombia. This study used 9 random amplified polymorphic DNA (RAPD) markers to analyze the mosquito's genetic variability and genetic structure of 122 specimens in 7 populations from the Colombian Atlantic coast. Assuming that all loci were in Hardy-Weinberg equilibrium, diversity statistics and analyses were performed. The average number of amplified fragments for each primer was 8.3, and the size of these fragments ranged from 350 to 3600 bp. The expected average heterozygosity was 0.358 ± 0.103. The genetic heterogeneity among the populations studied was small (GST = 0.05 ± 0.01); meanwhile, the gene flow estimates (Nm = 7.32 ± 1.35) were high. In an identical way, the Nei's genetic distances obtained yielded very small values amongst the populations that were studied in this Colombian region. Furthermore, a spatial autocorrelation analysis with Moran's I index revealed a very weak, or inexistent, spatial genetic structure among these populations. The comparison of these results with those performed for other markers (isoenzymes and microsatellites) in populations of this same mosquito from the Colombian Atlantic coast was discussed. The results of our RAPD analysis showed scarce genetic differentiation among the mosquito populations on the Colombian Atlantic coast, which was probably determined by high gene flow levels.

Genetic Variability in Four Alouatta Species Measured by Means of Nine DNA Microsatellite Markers: Genetic Structure and Recent Bottlenecks

We used microsatellite DNA to study the population genetics of 4 Alouatta species from Central and South America. Our main findings include the following: (1) A. seniculus had the highest level of microsatellite variability while A. caraya and A. palliata had the lowest mean number of alleles per locus and the lowest expected heterozygosity, respectively; (2) the samples of A. seniculus and A. palliata came from different regions and were not in Hardy-Weinberg equilibrium (HWE) which may indicate a Wahlund effect and differentiated gene pools -- in contrast, A. macconnelli and A. caraya were in HWE; (3) the microsatellite genetic heterogeneity of the 4 Alouatta species was similar to the karyotype divergence found among these Alouatta species; the species pair with the lowest level of heterogeneity (genetic differentiation) was A. seniculus/A. caraya, while the Central American species, A. palliata, was highly differentiated from the other 3 South American species; (4) we recommend the establishment of a conservation plan to help protect A. caraya because the Cornuet and Luikart procedure demonstrated a recent bottleneck for this species.

Genetic structure of the genera Psorophora (Diptera: Culicidae) in Columbian and North American populations using isoenzymes and ITS2 sequences

Two, a priori, Psorophora columbiae and one, a priori, Ps. toltecum populations from Colombia were studied by means of eleven isoenzyme loci. The levels of genetic diversity, Hardy-Weinberg equilibrium, gene flow estimates, isolation by distance and genetic relationships among these three populations were studied and the results were as follows: 1. The gene diversity levels were high as well as very similar among the three populations indicating no differences between them. 2. Within each population and from a hierarchical standpoint several loci were not in Hardy-Weinberg equilibrium simultaneously by excess and defect of heterozygous. This could reflect that several natural selection forces are acting upon these mosquito populations. 3. The gene flow estimate for these populations showed the existence of this event between them. This agrees quite well with the fact that the three populations really belong to a single species. In addition, maximum parsimony analyses with 16 isoenzyme for several individuals from four Colombian and two United States Psorophora populations showed that effectively only one species was present in the Colombian area surveyed, and that this species is Ps. columbiae, which hardly contrast with that previously suggested by other authors.

Mutant Allele Frequencies in Domestic Cat Populations in Arkansas and Tennessee

We conducted surveys of mutant allele frequencies of four cat populations in Arkansas and Tennessee during 2002. Our calculations and analyses support that Southwestern cat populations were relatively more genetically similar to each other than compared to cat populations in other areas of North America. However, the cat population of Fort Smith is slightly different from the other cat populations studied in the Southwestern United States. Although there is a clear significant spatial geographic pattern for many mutant coat allele frequencies in the United States and Canada cat populations (d, l, S, and W), our results revealed that there is not a significant isolation-by-distance model affecting these cat populations. Our data also support the historical migration hypothesis because our calculated allele frequencies were genetically similar to cat populations located in ancestral areas of Europe. Different phenograms, including new European cat genetic profiles, showed that the Southwestern cat populations studied are of a clear British origin. Therefore, migration routes of early Arkansas and Tennessee settlers help explain the similarities of allele frequencies among domestic cat populations.

Transcranial magnetic stimulation and acoustic trauma or hearing loss in children

Transcranial magnetic stimulation is a non-invasive method used to assess motor function in humans; however, some reports suggest it may cause internal ear damage (cochlear). Eighteen patients with normal auditory function (ages 2 months to 16 years, mean 6.8 years), two medical doctors and two technicians who performed the studies were tested with brain stem auditory evoked potentials, otoacoustic emissions, acoustic reflex and a pure tone audiometric and logoaudiometric test when possible, before and after transcranial magnetic stimulation for central motor conduction studies in different neurological conditions. All the tests were repeated two weeks and two months later. Patients had no auditory protection nor history of seizures. Motor evoked potentials and silent periods were recorded from the right abductor pollicis brevis and the first dorsal interosseous muscles at rest and during weak voluntary contraction when possible. A mean of 48 transcranial magnetic stimulations with 50%-75% Tesla intensity were used. Natural logarithmic transformation of latency and amplitude data had a normal distribution. There were no significant differences in auditory function testing.

Population Genetic Analysis of the Genes APOE, APOB (3′VNTR) and ACE in Some Black and Amerindian Communities from Colombia

A population genetic study was carried out with the APOE, APOB and ACE loci in 17 Colombian human populations. Ten of them were Amerindian communities coming from the northeastern part of Colombia, Pacific region, Eastern Plains and Amazonia. Six were black populations from Providence Island, Caribbean and Pacific coasts. Finally, the Mestizo population of Bogota was studied as well. The APOE and ACE loci were in Hardy-Weinberg equilibrium, whereas the APOB locus was not studied in all populations. The genetic heterogeneity was substantially greater among the Amerindian populations (G(ST) = 0.059) than in the Afrocolombian populations (G(ST) = 0.009). Also the gene flow population pair estimates were so much higher among the Afrocolombian populations (Nm = 49.08 +/- 43.07) than among Amerindian populations (Nm = 9.66 +/- 18.04). Different phylogenetic and multivariant analyses showed that the Amerindian populations analyzed were clustered in three different arrays: one constituted by the Colombian northeastern and Pacific populations, the second one by the two Amazon populations (Coreguaje and Nukak) and the last one by the Yuco (the unique Caribbe-speaking population among those studied). The latter population was highly divergent from a genetic point of view from the remainder Amerindian populations studied. By using the Mantel test, the existence of a positive and significant correlation between the genetic and geographical distances found among Amerindian populations was demonstrated. This fact was not observed among the Afrocolombian populations. Nevertheless, an isolation-by-distance Slatkin analysis test did not show a significant clear structure of this special pattern among the Indian tribes studied.

Population genetic analysis of Colombian Trypanosoma cruzi isolates revealed by enzyme electrophoretic profiles

Although Colombia presents an enormous biological diversity, few studies have been conducted on the population genetics of Trypanosoma cruzi. This study was carried out with 23 Colombian stocks of this protozoa analyzed for 13 isoenzymatic loci. The Hardy-Weinberg equilibrium, the genetic diversity and heterogeneity, the genetic relationships and the possible spatial structure of these 23 Colombian stocks of T. cruzi were estimated. The majority of results obtained are in agreement with a clonal population structure. Nevertheless, two aspects expected in a clonal structure were not discovered in the Colombian T. cruzi stocks. There was an absence of given zymodemes over-represented from a geographical point of view and the presumed temporal stabilizing selective phenomena was not observed either in the Colombian stocks sampled several times through the years of the study. Some hypotheses are discussed in order to explain the results found.

Genetic microstructure in two Spanish cat populations. II: gametic disequilibrium and spatial autocorrelation

In a previous publication, we described some aspects of the microgenetic structure of two Spanish cat populations (in Barcelona and Alicante). In the present study, the possible existence ofgametic disequilibrium and spatial genetic structure for these populations, at the coat colour pattern and length genes O, A, T D, L, S and W, was analyzed. There was little gametic disequilibrium between pairs of these loci, despite certain pairs that showed significant systematic gametic disequilibrium (a-d and O-S), which appears to show the action of natural selection on domestic cat populations. Nevertheless, we believe that the major cause of the small amount of gametic disequilibrium found was probably a combination of gene drift and gene flow. The results obtained here were clearly in disagreement with those of Hedrick (1985), who concluded that epistatic selection was the cause of the gametic disequilibrium that he found in cat populations. We also found that although Hardy-Weinberg equilibrium could not be demonstrated, the gametic disequilibrium statistics were not affected by this fact, adding credence to the estimates obtained. We found no genetic spatial structure inside the city of Barcelona, as shown by analysis of the spatial autocorrelation of the individual loci, and analysis of the coordinates of the two first axes of a multidimensional scale. However, some gametic disequilibrium statistics showed certain spatial patterns, which leads us to consider the possibility of several evolutionary processes acting upon some of Barcelona's cat colonies.

Genetic relationships and spatial genetic structure among clonal stocks of Trypanosoma cruzi in Colombia

Genetic variability in the protozoan causative agent of Chagas' disease, Trypanosoma cruzi, has been analysed in some Latin American countries; Brazil, Bolivia, Chile and Paraguay. Although Colombia is a country displaying enormous biological diversity, few studies have been conducted from the perspective of the population genetics of Trypanosoma cruzi. This study was carried out using 23 Colombian stocks of this protozoan, analysed for 13 isoenzyme loci. The main population genetic results were: (1) Colombia is one of the distribution areas where T. cruzi appears to have the highest genetic variability and heterogeneity in Latin America; (2) the Pgm locus was found in fixed heterozygosis, supporting the presence of diploidy in this organism; (3) the absence of segregating genotypes and the absence of Hardy-Weinberg equilibrium support the view of the existence of a clonal structure as claimed by Tibayrenc and Ayala. Nevertheless, one characteristic of clonal structure, that of over-representation of some identical zymodemes in vast areas of varying environmental conditions, was not found in Colombia. In this country, a strong spatial autocorrelation, with a classic structure of regional patches, was observed.

Genetic microstructure in two Spanish cat populations. I: genic diversity, gene flow and selection

The genetic microstructure of two Spanish cat populations (in Barcelona and Alicante) was studied. These populations were in Hardy-Weinberg equilibrium at the locus O . There was significant genetic heterogeneity for most of the loci studied at the colony level, especially, and the subpopulation level in Barcelona, and at the subpopulation level in Alicante, although the amount of heterogeneity was relatively small compared with that found in other mammal species. Therefore, the major part of the gene diversity found was at the level of the small population structure (colonies). This agrees quite well with high theoretical gene flow estimates. The Lewontin-Krakauer test showed, in some cases, significant F tests, which appears to indicate the presence of several selective events on some of the loci studied (diversifying and/or unifying), although some other causes, such as differential gene flow, some different historical and demographic parameters at the time of the introduction of the different alleles within the cities studied, as well as different mutation rates of the loci analyzed, could produce significant Lewontin-Krakauer test values, as well.

Is there really natural selection affecting the l frequencies (long hair) in the Brazilian cat populations?

The scientific literature on cat genetics contains a presumed typical example of natural selection affecting l frequencies (long hair) in 16 Brazilian cat populations. It has been observed that the hotter and more tropical the climate in Brazil, the lower the values of l frequencies in the cat populations. Nevertheless, this study of some new cat populations in Latin America showed that all of them, independent of the climate, had high or very high l frequencies. l postulate that an alternative migrational-historical hypothesis exists that explains the correlation between the l frequencies and climate characteristics (which are correlated with the latitude) without using natural selection explanations concerning the appearance of the l allele in Brazil.

Early detection of neurological manifestations in achondroplasia

Achondroplasia (ACh) is the most frequent bone dysplasia. The mode of inheritance is autosomal dominant. The incident of neurological complications ranges between 20% and 47%; frequently the symptoms are subtle but are due to such serious conditions as cervicomedullary compressive syndromes, syringomyelia or hydrocephalus; thus, the early identification of this disorder is very important. We made a prospective study of 39 patients (20 female, 19 male) with ACh; their ages ranged from 3 months to 17 years (mean 4 years and 6 months). All patients had hypotonia and psychomotor delay; 3 had recurrent apnea, 1 developed radicular syndrome and 1 had leg paresthesias. The CT scan was normal in 5, 20 had cortical atrophy and 18 communicating hydrocephalus; we identified foramen magnum abnormalities in 28 patients, and reduced craniocervical junction with cervicomedullary compression in 6. Myelography and myelotomography demonstrated spinal compression in 12 patients. The MRI showed cervicomedullary infarct in 1, syringomyelia in 2 and diastematomyelia in 1. The somatosensory evoked responses (SSER) were very useful in the early identification of brain stem and spinal abnormalities. We concluded that the neurological manifestations of pediatric patients with ACh are frequent and very important, demanding comprehensive clinical evaluation even in asymptomatic patients, especially those with severe hypotonia or SSER alterations.