Defining tetrahydrobiopterin responsiveness in phenylketonuria: Survey results from 38 countries

BACKGROUND

A subset of patients with phenylketonuria benefit from treatment with tetrahydrobiopterin (BH4), although there is no consensus on the definition of BH4 responsiveness. The aim of this study therefore was to gain insight into the definitions of long-term BH4 responsiveness being used around the world.

METHODS

We performed a web-based survey targeting healthcare professionals involved in the treatment of PKU patients. Data were analysed according to geographical region (Europe, USA/Canada, other).

RESULTS

We analysed 166 responses. Long-term BH4 responsiveness was commonly defined using natural protein tolerance (95.6%), improvement of metabolic control (73.5%) and increase in quality of life (48.2%). When a specific value for a reduction in phenylalanine concentrations was reported (n = 89), 30% and 20% were most frequently used as cut-off values (76% and 19% of respondents, respectively). When a specific relative increase in natural protein tolerance was used to define long-term BH4 responsiveness (n = 71), respondents most commonly reported cut-off values of 30% and 100% (28% of respondents in both cases). Respondents from USA/Canada (n = 50) generally used less strict cut-off values compared to Europe (n = 96). Furthermore, respondents working within the same center answered differently.

CONCLUSION

The results of this study suggest a very heterogeneous situation on the topic of defining long-term BH4 responsiveness, not only at a worldwide level but also within centers. Developing a strong evidence- and consensus-based definition would improve the quality of BH4 treatment.

PKU dietary handbook to accompany PKU guidelines

Background

Phenylketonuria (PKU) is an autosomal recessive inborn error of phenylalanine metabolism caused by deficiency in the enzyme phenylalanine hydroxylase that converts phenylalanine into tyrosine.

Main body

In 2017 the first European PKU Guidelines were published. These guidelines contained evidence based and/or expert opinion recommendations regarding diagnosis, treatment and care for patients with PKU of all ages. This manuscript is a supplement containing the practical application of the dietary treatment.

Conclusion

This handbook can support dietitians, nutritionists and physicians in starting, adjusting and maintaining dietary treatment.

The complete European guidelines on phenylketonuria: diagnosis and treatment

Phenylketonuria (PKU) is an autosomal recessive inborn error of phenylalanine metabolism caused by deficiency in the enzyme phenylalanine hydroxylase that converts phenylalanine into tyrosine. If left untreated, PKU results in increased phenylalanine concentrations in blood and brain, which cause severe intellectual disability, epilepsy and behavioural problems. PKU management differs widely across Europe and therefore these guidelines have been developed aiming to optimize and standardize PKU care. Professionals from 10 different European countries developed the guidelines according to the AGREE (Appraisal of Guidelines for Research and Evaluation) method. Literature search, critical appraisal and evidence grading were conducted according to the SIGN (Scottish Intercollegiate Guidelines Network) method. The Delphi-method was used when there was no or little evidence available. External consultants reviewed the guidelines. Using these methods 70 statements were formulated based on the highest quality evidence available. The level of evidence of most recommendations is C or D. Although study designs and patient numbers are sub-optimal, many statements are convincing, important and relevant. In addition, knowledge gaps are identified which require further research in order to direct better care for the future.

[Medication-related oculogyric crises: a description of four cases and a review of the literature]

INTRODUCTION

Oculogyric crises are considered to be a form of focal dystonia and can be observed as reactions to pharmaceuticals. The signs and symptoms may be confused with epileptic crises.

AIMS

To describe the clinical features and progress of patients with pharmaceutical-related oculogyric crises and to carry out a review of the topic.

CASE REPORTS

We conducted a retrospective, descriptive study of four patients evaluated in the neurology service due to oculogyric crises. The patients had been diagnosed with an associated conduct disorder requiring treatment with antipsychotic drugs. The episodes of oculogyric crises did not correlate with the findings in the electroencephalogram. They responded well to the reduction in dosage or to withdrawal of the apparent causing agent.

CONCLUSIONS

The clinical picture does not present only in patients treated with antipsychotics but is also linked with other pharmaceuticals that are frequently used in daily paediatric practice. When oculogyric crises are the reason for visiting, differential diagnoses must be taken into account in order to avoid unnecessary studies and to carry out an appropriate therapeutic management.

[Amino acids in cerebrospinal fluid and plasma: its usefulness in the study of neuropaediatric diseases]

INTRODUCTION

Studying the amino acids in cerebrospinal fluid (CSF) is essential in the diagnosis of some neurological diseases and is an important aid in the diagnosis of others. No research has been published in the literature to prove the physiological relationship between the values of amino acids in CSF and plasma in the paediatric population.

AIM

To define a set of ratios for amino acids in plasma and CSF in the paediatric population that can be used in daily clinical practice.

PATIENTS AND METHODS

The aminograms in plasma and CSF of 105 patients with ages between 0 and 12 months were collected and analysed retrospectively. Aminograms with amino acid values that are considered to be normal according to the reference values of our laboratory were included in the sample. The quantitative analysis of amino acids was performed using high-resolution liquid chromatography and statistical analysis with the software application SPSS 19.0.

RESULTS

The mean values, range and standard deviation of the amino acid concentrations in plasma and CSF, together with the CSF/plasma ratios, are reported. Significant correlations were found from 0.6 onwards between different neutral amino acids, above all in those with smaller molecular weights (Thr, Ser, Gly and Ala).

CONCLUSIONS

The existence of significant correlations between the different neutral amino acids supports the idea that they share the same transporters in the blood-brain barrier. Standardising the amino acid ratios will make it possible to increase sensitivity in the detection of pathological values in plasma and CSF, to further knowledge of the pathophysiology of neurological diseases and perhaps to describe new aminoacidopathies.

Hypokinetic-rigid syndrome in children and inborn errors of metabolism

Hypokinetic-rigid syndrome (HRS) or "parkinsonism" is rare in children. From a clinical point of view it is characterised by a group of signs in which hypokinesia (decreased number of movements), bradykinesia (slowness of movements), rigidity and rest tremor are the fundamental traits. Nervous system infections, immunomediated encephalitis, hypoxia and some drugs have been described as acquired or secondary causes of HRS in the paediatric age. Inborn errors of metabolism (IEM) comprise and important group regarding genetic causes. Main diseases causing HRS in children are neurotransmitter (biogenic amines) defects, metal storage diseases, energy metabolism disorders and lysosomal diseases. In general, in IEM, the HRS is associated to other neurological signs such as dykinesias, pyramidal signs, and psychomotor delay, is very rare in the neonatal period, tends to be more frequent in advanced stages of progressive diseases, and may respond to specific therapies. In particular, l-dopa + carbidopa can be a very effective treatment in neurotransmitter defects, whereas other disorders such as Wilson disease and some particular lysosomal disorders have different therapeutic possibilities. Furthermore, other genetic conditions in dopa-responsive and non-responsive HRS should be also considered, especially in juvenile parkinsonism. Through this review, a practical orientation for paediatric neurologists concerning clinical clues, diagnostic procedure and treatment of metabolic HRS will be provided.

[Predictive variables for mental retardation in a Pediatric Epilepsy Monitoring Unit. Neuropsychological assessment]

AIM

We sought to describe the epidemiological and clinical data from our patients in the Pediatric Epilepsy Monitoring Unit (PEMU) of the Sant Joan de Deu Hospital of Barcelona, and determine the variables of risk for mental retardation.

PATIENTS AND METHODS

A retrospective review of PEMU reports and hospital discharge summaries from March 2005 to December 2008 was conducted. The data from patients with intelligence quotient (IQ) estimated, older than 3 years of age and with epileptic electroencephalography (EEG) activity was analyzed in 158 patients (8.8 +/- 5.2 years; 55.1% boys). Of those pediatric patients, 63 had IQ less than 70 and 47 an IQ greater than or equal to 70. Intractable epilepsy was present in all of them.

RESULTS

The percentage of the patients with mental retardation is significantly higher in patients with onset of epilepsy before 24 months (68.3%) than patients with later onset (27.7%). Onset of seizures, EEG findings and epilepsy etiology are significant risk factors for mental retardation.

CONCLUSIONS

Early age at seizure, multifocal epilepsy and cryptogenic etiology are factors of worse prognosis to normal development of cognitive functions in pediatric intractable epilepsy.

Response to creatine analogs in fibroblasts and patients with creatine transporter deficiency

Creatine transporter (CRTR) deficiency is one of the most frequent causes of X-linked mental retardation. The lack of an effective treatment for this disease, in contrast to creatine (Cr) biosynthesis disorders that respond to Cr monohydrate (CM), led us to analyze the efficacy of a lipophilic molecule derived from Cr, creatine ethyl ester (CEE), in fibroblasts and patients with CRTR deficiency. CM and CEE uptake studies were performed in six controls and four fibroblast cell lines from patients. We found a significant increase in Cr uptake after 72 h of incubation with CEE (500 micromol/L) in patients and control fibroblasts compared to incubation with CM. Subsequently, we assayed the clinical effect of CEE administration in four patients with CRTR deficiency. After 1 year of treatment, a lack of significant improvement in neuropsychological assessment or changes in Cr level in brain (1)H MRS was observed, and CEE was discontinued. In conclusion, this 12-month trial with CEE did not increase the brain concentration of Cr. Our in vitro data lend support to the idea of a certain passive transport of CEE in both pathological and control cells, although more lipophilic molecules or other cell systems that mimic the BBB should be used for a better approach to the in vivo system.

A phase III study of belatacept versus cyclosporine in kidney transplants from extended criteria donors (BENEFIT-EXT study)

Recipients of extended criteria donor (ECD) kidneys are at increased risk for graft dysfunction/loss, and may benefit from immunosuppression that avoids calcineurin inhibitor (CNI) nephrotoxicity. Belatacept, a selective costimulation blocker, may preserve renal function and improve long-term outcomes versus CNIs. BENEFIT-EXT (Belatacept Evaluation of Nephroprotection and Efficacy as First-line Immunosuppression Trial-EXTended criteria donors) is a 3-year, Phase III study that assessed a more (MI) or less intensive (LI) regimen of belatacept versus cyclosporine in adult ECD kidney transplant recipients. The co-primary endpoints at 12 months were composite patient/graft survival and a composite renal impairment endpoint. Patient/graft survival with belatacept was similar to cyclosporine (86% MI, 89% LI, 85% cyclosporine) at 12 months. Fewer belatacept patients reached the composite renal impairment endpoint versus cyclosporine (71% MI, 77% LI, 85% cyclosporine; p = 0.002 MI vs. cyclosporine; p = 0.06 LI vs. cyclosporine). The mean measured glomerular filtration rate was 4-7 mL/min higher on belatacept versus cyclosporine (p = 0.008 MI vs. cyclosporine; p = 0.1039 LI vs. cyclosporine), and the overall cardiovascular/metabolic profile was better on belatacept versus cyclosporine. The incidence of acute rejection was similar across groups (18% MI; 18% LI; 14% cyclosporine). Overall rates of infection and malignancy were similar between groups; however, more cases of posttransplant lymphoproliferative disorder (PTLD) occurred in the CNS on belatacept. ECD kidney transplant recipients treated with belatacept-based immunosuppression achieved similar patient/graft survival, better renal function, had an increased incidence of PTLD, and exhibited improvement in the cardiovascular/metabolic risk profile versus cyclosporine-treated patients.

Cognitive functions in patients with phenylketonuria in long-term treatment with tetrahydrobiopterin

Cognitive functions were assessed in 9 patients with mild to moderate phenylketonuria (PKU) ranging from 6 to 18 years of age, who were in long-term treatment (>5 years) with 5-9 mg/kg/day tetrahydrobiopterin (BH4) on compassionate use, provided by Schircks Inc. An extensive study of cognitive functions (intelligence quotient (IQ), visuospatial, visual memory, fine motor, executive and attentional functions) was conducted, and behavior was assessed using the ADHD Rating Scale and the Behavior Rating Inventory of Executive Function (BRIEF). All patients had normal IQ (M=107, SD=10). The most notable area of impairment was fine motor function, but no significant difference was found between the PKU patients in BH4 treatment who participated in the current study and PKU patients in dietary treatment who participated in a previous study. These results, however, should be interpreted with caution. It is necessary to conduct further studies with a larger number of patients, using more sensitive tests of motor function and using the formulation of BH4 that is currently available.

Quality of dietary control in phenylketonuric patients and its relationship with general intelligence

OBJECTIVES

Assessment of the quality of dietary treatment of phenylketonuria (PKU) patients and investigation of its relationship with the general intelligence of the patients.

METHODS

Cross-sectional and longitudinal study of 105 PKU treated patients. The index of dietary control (IDC) was calculated as the phenylalanine (Phe) data reduction in half-year medians and the mean of all medians throughout the patient's life. We calculated four different IDCs related to age: IDC-A (< 6 years), IDC-B (6-12 years), IDC-C (13-18 years) and IDC-D (> 18 years). To evaluate the fluctuation of Phe values we calculated the standard error of the estimate of the regression of Phe concentration over age. Development quotient was calculated with the Brunet-Lezine test (< 4 years). Intelligence quotient was evaluated with the Kaufman Bit Intelligence Test (K-Bit), Wechsler Intelligence Scale for Children-Revised (WISC-R) and Wechsler Adult Intelligence Scale Third Edition (WAIS III).

RESULTS

Cross-sectional study: The IDC in age groups were significantly different and so were the number of patients with good, acceptable and poor IDC related to age (p < 0.001). Sampling frequency was good in 72, acceptable in 23 and poor in 10 patients. The general intelligence (101 +/- 10) correlated negatively with the IDC (p < 0.0001) and Phe fluctuations (p < 0.004). Longitudinal study: Significant differences were observed between the IDC through the patients' lifetime except in the adolescent/adult period.

CONCLUSIONS

85% of PKU patients showed good/acceptable quality of dietary control. General intelligence correlates with the IDC at all ages, which highlights the importance of good control to achieve good prognosis.

Creatine transporter deficiency in two adult patients with static encephalopathy

Creatine transporter deficiency is a recently identified X-linked inborn error of metabolism. The natural course of the disease is not well delineated since clinical data from adult patients have scarcely been reported. A progressive course of the disease has been noted in a few described cases. We report the first two Spanish adult patients with creatine transporter deficiency and compare their clinical phenotype and the evolution of the disease with those of other published cases. The two brothers were identified in a study of a cohort of 610 mentally handicapped male patients. The disease was detected by biochemical studies and confirmed by DNA studies. The most significant clinical features were mental retardation, epilepsy and autistic behaviour, and these symptoms did not worsen, in contrast to other reports. They did not present gastrointestinal problems or movement disorders. Creatine transporter deficiency could be an underdiagnosed metabolic disorder and should be considered in adult patients with mental retardation. Clinical presentation of this disorder showed marked differences among adult patients and the course of the disease was static in our cases. Detection of additional adult patients might allow better understanding of the phenotypic outcome at a later age.

Mental retardation and inborn errors of metabolism

In countries where clinical phenylketonuria is detected by newborn screening inborn errors of metabolism are rare causes of isolated mental retardation. There is no international agreement about what type of metabolic tests must be applied in patients with unspecific mental retardation. However, and although infrequent, there are a number of inborn errors of metabolism that can present in this way. Because of the high recurrence risk and the possibility of specific therapies, guidelines need to be developed and adapted to different populations. The application of a universal protocol may result in a low diagnostic performance in individual ethnic populations. Consideration of associated signs (extraneurological manifestations, psychiatric signs, autistic traits, cerebellar dysfunction, epilepsy or dysmorphic traits) greatly improves the diagnostic fulfilment.

Inborn errors of metabolism and motor disturbances in children

Motor disturbances are very common in paediatric neurology. Often families can be reassured that these are just variants of normal development. However, abnormal movements can also be the hallmark of severe brain dysfunction of different and complex origins. This review concentrates on motor disturbances as frequent and important symptoms of inborn errors of metabolism. A structured diagnostic approach is developed taking into account age-dependent physiological developments and pathophysiological responses of gross and fine motor functions. A series of investigations are presented with the primary aim of early diagnosis of treatable conditions. The correct recognition and differentiation of movement disorders (ataxia, rigid akinetic syndrome (Fparkinsonism_), dystonia, athetosis, tremor,and others), spasticity, and neuromuscular disorders, requires profound neurological expertise. A high level of suspicion and close interaction between paediatric neurologists and specialists in inborn errors of metabolism are indispensable to effectively and timely identify patients in whom motor disturbances are the presenting and/or main symptom of an inborn error.

Long-term evolution of eight Spanish patients with CDG type Ia: typical and atypical manifestations

Congenital disorder of glycosylation Ia (CDG-Ia) is a metabolic disease with a broad spectrum of clinical signs, including recently described mild phenotypes. Our aim was to describe the clinical presentation and follow-up of eight CDG-Ia patients highlighting atypical features and aspects of evolution of the disease. CDG diagnosis was confirmed by enzymatic analysis of phosphomannomutase (PMM2) and molecular studies of the PMM2 gene. Four neonates presented with cerebral haemorrhage (1), failure to thrive (2) and non-immune hydrops (1) and a fatal course to death (2); pathological examination of the brain in one case revealed olivopontocerebellar atrophy of prenatal origin. During infancy failure to thrive, coagulopathy and hepatopathy were the most significant causes of morbidity, but these disappeared after the first years of life in most patients. Three patients are currently in their 20s; they present mental retardation and severe motor impairment but no acute decompensations were noticed after the first decade of life. They do not present spinal or thoracic deformities otherwise observed in patients from northern countries. A 10-year-old patient who manifested gastrointestinal dysfunction in early childhood showed normal neurodevelopment. Mutation analysis of the PMM2 gene showed great variability, with all patients being compound heterozygous for two different mutations. Long-term evolution in our patients indicates that CDG-Ia is a stable systemic and neurological condition after the first decade of life. The diverse phenotypes and atypical manifestations in our series may be due to their genetic heterogeneity.

Arginine supplementation in four patients with X-linked creatine transporter defect

BACKGROUND

Treatment with oral creatine monohydrate has not shown efficacy in patients with creatine transporter deficiency (CRTR-D). Another therapeutic option proposed is L-arginine, the substrate for the enzyme L-arginine:glycine amidinotransferase (AGAT). We evaluate clinical characteristics and cerebral creatine replenishment after L-arginine therapy in four patients with CRTR-D.

PATIENTS AND METHODS

Four boys with genetically confirmed diagnosis of CRTR-D (ages 9-16 years) were supplemented with L-arginine (0.4 g/kg per day) for a period of 9 months. Treatment efficacy was evaluated by clinical and neuropsychological assessment and determination of creatine signals by brain proton magnetic resonance spectroscopy ((1)H-MRS).

RESULTS

Epileptic seizures remained well controlled with antiepileptic drugs in three cases, both before and after L-arginine supplementation. Vineland Adaptive Behaviour Scale did not show any change in communication, daily living skills, socialization or motor skills, and a lack of improvement in brain (1)H-MRS follow-up was observed. L-Arginine was discontinued at the end of the observation period.

CONCLUSIONS

Nine months of L-arginine supplementation did not show effectiveness in the four patients affected with CRTR-D in this protocol.

[Neurologic presentation in haemolytic-uraemic syndrome]

INTRODUCTION

Haemolytic-uraemic syndrome (HUS) is characterized by microangiopathic hemolytic anaemia, thrombopenia and multiorganic aggression, specially renal, gastrointestinal and central nervous system disturbances. Sporadic in Spain (2/1,500,000 inhabitants), its clinical onset includes acute renal failure, hypertension and central nervous system symptoms (irritability, drowsiness, convulsions, cortical blindness, hemiparesia or coma), due to metabolic distress, hypertension or central nervous system microangiopathy. Few long-term outcome studies have been published.

PATIENTS AND METHODS

A retrospective analysis of a series of 58 patients with HUS between 1981 and 2006, is reported. Clinical onset, laboratory, electrophysiology, neuroimaging tests, and prognosis factors are reviewed, together with long-term clinical outcome.

RESULTS

22 children presented neurologic symptoms, seven had some neurological test; one patient died; in five some neurological sequelae persisted (hemiparesia, cognitive deficit, visual-perception deficit), the other 16 remaining asymptomatic.

CONCLUSIONS

Neurological morbility is high in HUS (27% of the children with neurological symptoms), with a 1.7% mortality. Seizure at onset was not a poor prognosis factor in our group. No positive correlation can be established between neuroimaging and long-term outcome.

[Moyamoya disease among children. An analysis of a series in the Western world and literature review]

PATIENTS AND METHODS

A total of 12 patients with moyamoya disease or syndrome with a mean age of 6 years were analyzed in a retrospective fashion.

RESULTS

Infarction was the most frequent presentation feature (8 out of 12 patients), 2 had epilepsy and 2 were incidental findings. Seven cases were classified as idiopathic while the other five were related to systemic illnesses. Diagnosis was initially made by magnetic resonance angiography in 9 cases, and conventional angiography in 3 cases. Mean follow-up is 5 years; six patients experienced clinical worsening of symptoms, while 6 cases remained clinically stable. However, all of them showed angiographic progression. Four patients underwent revascularization surgery. Two children died due to complications associated with moyamoya disease, and six have moderate handicaps.

CONCLUSION

Due to the fact moyamoya disease is not an indolent disorder and readily progress to cause complications, surgical revascularization should always be considered in the management of these patients.

[Clinical characteristics and progress of patients with migrainous headaches monitored in the Headache Unit in a paediatric referral hospital]

AIM

To analyse the clinical characteristics and course of migraine patients who were attended in the Headache Unit of a paediatric referral hospital.

PATIENTS AND METHODS

We conducted a retrospective observational study of children monitored in the Headache Unit of the Neurology Service who satisfied the International Headache Society diagnostic criteria for migraine, with a follow-up lasting more then six months. The following were excluded from the study: patients who failed to comply with the treatment or clinical monitoring, or whose medical data were incomplete.

RESULTS

There was a predominance of patients aged between 7 and 12 years, with no differences as regards sex. Bilateral and frontal migraine without aura predominated (74%), with episodes lasting between 3 and 12 hours, and the throbbing type accounted for 45% of cases. The most common accompanying symptoms were photophobia (86%) and phonophobia (88%). Except for the second visit, the tendency of the group without prophylactic treatment was favourable. When prophylactic treatment was indicated, a favourable response was observed (p < 0.05), and no significant differences were found as regards the type of medication employed. A total of 73% of the patients were discharged, and most of them required three visits; 30% of the patients treated reported some kind of side effects.

CONCLUSIONS

Migraine at the paediatric age is characterised by short but intense episodes of headache that are mostly located in the frontal area. Progress is satisfactory without pharmacological measures in a high percentage of patients. When prophylactic medication was required (due to the patient's presenting frequent episodes of migraine with high scores on the PedMIDAS rating scale), a favourable response was obtained (p < 0.05), with some side effects.

[Multiple familial cerebral cavernomatosis]

INTRODUCTION

Intracraneal vascular malformations are congenital lesions due to alterations in the development of arteriocapillary network. Cavernomas are present in 0.4% of people, and represent 5-13% of all cerebrovascular malformations. They are multilobulated clearly delimited lesions that contain blood at different evolution. Cavernomas can be single or multiple, and sporadic or familial. Inheritance pattern in familial cases is autosomal dominant and three involved genes have been described.

CASE REPORTS

We made a retrospective review of clinical histories of two patients diagnosed of multiple familial cavernomatosis. First patient's onset was with partial seizures. Magnetic resonance (MR) showed a frontal cavernoma probable responsible of seizures, and other lesions in frontal and parietal lobes. Second patient consulted for psychomotor delay and behaviour disorder. MR showed multiple cavernomas. In the first patient, one lesion was surgically removed. In second patient, the attitude was expectant. In both cases familial study was done and multiple cavernomas were found in both parents.

CONCLUSIONS

Cavernomas are a type of vascular malformations with specific histological features. Usual clinical characteristics are seizures and parenchymatous bleeding. The appearance of MR has permitted the diagnosis of asymptomatic cavernomas and is currently considered to be the technique of choice for this purpose. In familial cases, multiple lesions are found in 84%, often in association with family history of seizures. Surgical treatment must be considered in patients with symptomatic or progressive lesions that are accessible. All cases must be clinically and MR followed.

[Newborn neurometabolic diseases as a cause of neurodevelopmental disorders]

INTRODUCTION

Foetal distress and hypoxic-ischaemic encephalopathy are two of the most frequent causes of neonatal morbidity and mortality. They can be caused by a number of factors. Uterine and intrapartum asphyxia are the two most common causes; nevertheless, there are also other causing factors that are not usually considered, such as inborn errors of metabolism (IEM), for example. Manifestations can be very different, not particularly specific and easily mistaken for the first two situations. The neonatologist and, later, the neuropaediatrician must be familiar with the initial clinical-biochemical presenting symptoms, as they can often mimic the clinical picture of hypoxic-ischaemic encephalopathy or the foetal distress. Once the most common causes have been ruled out and working in collaboration with the clinical biochemist and neuropaediatrician, they will be able to offer guidance on the complex diagnostic and therapeutic approach. In recent years, the combination of the wider experience held by departments and modern laboratory techniques has made it possible to establish much earlier diagnoses and treatments that are of greater benefit to the affected patients.

DEVELOPMENT

In this review we analyse the clinical presenting symptoms in a consecutive series of 51 newborn infants with neurological manifestations and who were finally diagnosed with IEM.

CONCLUSIONS

The diagnostic approach and prognosis will vary considerably, while genetic counselling can be offered and prenatal diagnosis can sometimes be performed. Unfortunately, the prognosis of IEM with inborn neurological manifestations is still uncertain and the morbidity and mortality rates remain high.

[Moebius sequence: clinico-radiological findings]

INTRODUCTION

Moebius syndrome is an infrequent congenital, non-progressive disorder that is defined by facial palsy (usually bilateral) and oculomotor compromise. Its clinical spectrum is variable but it affects other cranial nerves and is associated with multiple malformations.

PATIENTS AND METHODS

We report the clinical, neurological and neuroimaging features and the progress of 20 patients (16 males and 4 females) who satisfied diagnostic criteria for Moebius sequence.

RESULTS

Ages at the first visit ranged from 9 days to 23 months. Births had been normal in 50% of the patients. Facial nerve compromise was observed in all cases, 70% being bilateral. Cranial nerves VI (85%), XII (40%), VIII (25%) and IX (60%) were also involved. Perinatal respiratory distress was seen in 35% of the patients, apnoeas in 25% and retarded development in 60% of cases. They also presented other associated malformations such as microretrognathia, ogival palate, club foot, hand and foot malformations, and four cases presented unilateral agenesis of the pectoralis major. An electromyogram study showed absence of spontaneous and voluntary activity and muscle evoked potentials on stimulating the facial nerve; magnetic resonance imaging of the brain showed hypoplasia of the trunk, agenesis of the cranial nerves and abnormalities in the posterior fossa in three of the ten cases in which the scan was performed.

CONCLUSIONS

The association of multiple malformations and dysfunction of the cranial nerves suggests a disruption in the process of morphogenesis during the embryonic period, and therefore Moebius syndrome is considered to be a malformative sequence.

[Cerebral creatine transporter deficiency: an infradiagnosed neurometabolic disease]

INTRODUCTION

Brain creatine deficiencies are a group of inborn errors of metabolism recently recognized which are caused by arginine: glycine amidinotransferase (AGAT) deficiency, guanidinoacetate metiltransferase (GAMT) deficiency and defects in creatine transporter (CRTR). Although all of them are characterized by a brain creatine deficiency, clinical and biochemical features are different.

CASE REPORTS

We present a retrospective study about four patients of masculine sex affected of creatine transporter defects who were recently diagnosed in our centre. We describe the clinical presentation features, the different tests that we used in the diagnosis process (brain magnetic resonance spectroscopy, biochemical analysis of guanidinoacetate and creatine/creatinine ratio in urine), evolution aspects and the response to treatment. The most significative clinical feature was developmental delay mainly in expressive speech, they also presented epilepsy (three cases), autism (three cases), hypotonia (one case) and microcephalia (one case). Brain magnetic resonance spectroscopy showed a low (three cases) or an absence (one case) of creatine level. To confirm the defect we studied the creatine uptake in fibroblasts and molecular analysis of the SLC6A8/creatine transporter gene. Patients with creatine transporter deficiency are being treated with arginine, because a lack of response to creatine.

CONCLUSION

Cerebral creatine transporter deficiency can present with different neurological symptoms but developmental and language delay and epilepsy are the most significative; diagnosis is easy and there are some therapeutical options.

[Orientation of mental retardation from neurometabolic diseases]

INTRODUCTION AND DEVELOPMENT

Isolated mental retardation is rarely caused by metabolic factors. The application of a standardised protocol offers low diagnostic performance. There is no international agreement about what type of metabolic examination must be applied in patients with unspecific mental retardation. Nevertheless, and although they are infrequent, there are a number of inborn errors of metabolism that can present in this way. Urea cycle disorders, different forms of homocystinuria, creatine transport deficiency, 4-hydroxybutyric aciduria, Sanfilippo disease, adenylosuccinate lyase deficit and certain extraordinarily rare congenital disorders of the glycosylation of proteins are some examples of them. It is important first to consider those for which treatment is available and that could be diagnosed genetically for possible family counselling.

CONCLUSIONS

Rather than applying a standardised study protocol it is essential is to perform a thorough appraisal of the signs and symptoms associated with the mental retardation (psychiatric disorders, autistic traits, predominant compromise of language, signs of cerebellar dysfunction, epilepsy, dysmorphic traits), since in most disorders it is necessary to apply specific analyses, which are not included in conventional metabolic studies and are only available in certain reference centres.

[Effectiveness and safety of levetiracetam in 133 children with medication resistant epileptic seizures]

INTRODUCTION

Levetiracetam (LEV) is the latest drug approved in the European Union for use in polytherapy in children over 4 years of age with partial epileptic seizures that are resistant to other antiepileptic drugs. AIM. To report our experience of associating LEV in children with medication resistant epileptic seizures.

PATIENTS AND METHODS

We conducted an open, observational, respective study involving 133 children with refractory epilepsies: 106 with focal seizures and 27 with other types of seizures. LEV was associated over a period of more than 6 months and we evaluated its repercussion on the frequency of the seizures and the side effects related to the drug.

RESULTS

With average doses of LEV of 1,192 +/- 749 mg/day the frequency of the seizures was reduced by over 50% in 58.6% of cases and seizures were quelled in 15.8% of patients. Side effects were produced in 27.8% of cases, and were usually transient or tolerable; these effects led to withdrawal of LEV in only eight cases (6.02%). In 37 children (27.8%), their relatives noted an improvement in their social behaviour and cognitive abilities.

CONCLUSIONS

a) LEV is an effective drug that is well tolerated in children with refractory epilepsy; b) Its effectiveness in different types of seizures indicates a broad therapeutic spectrum; and c) LEV can even condition favourable secondary effects, a circumstance that has been reported only exceptionally in the case of other antiepileptic drugs.

[Diagnosis and treatment of brain creatine deficiency syndromes]

AIM

To review the clinical, biochemical and genetic aspects of brain creatine deficiency syndromes, as well as the therapeutic options available.

DEVELOPMENT

Brain creatine deficiency syndrome has recently been described as a series of inborn errors of metabolism that affect the synthesis and transport of creatine. Three metabolic defects are known: two affect synthesis -guanidinoacetate methyltransferase (GAMT) and arginine:glycine amidinotransferase (AGAT)- and one affects the transport of creatine. Clinically, these patients can display mental retardation, language disorders, epilepsy, autistic behaviour, neurological impairment and movement disorders. After the clinical selection, the different defects can be identified by a biochemical study involving the analysis of metabolites in biological fluids (guanidinoacetate and creatine/ creatinine ratio). Before continuing with the molecular studies, it is important to confirm the deficiency of brain creatine by means of magnetic resonance imaging with spectroscopy. Diagnostic confirmation of AGAT and GAMT deficits is carried out by determining the enzymatic activity in fibroblasts or lymphoblasts, or the incorporation of creatine in the case of studies of transport defects. The study of mutations in AGAT, GAMT (autosomal recessive inheritance) and SLC6A8 (X-linked) genes completes the diagnosis.

CONCLUSIONS

Brain creatine deficiency syndromes are mainly associated to mental retardation and autism. GAMT and AGAT deficiencies respond to treatment with creatine, whereas patients with transport defects do not respond to this therapy; new therapeutic approaches are therefore being evaluated for this disease.

Effects of oxcarbazepine on cognitive function in children and adolescents with partial seizures

The authors investigated the effect of oxcarbazepine on cognitive function in children and adolescents (6 to younger than 17 years of age) with newly diagnosed partial seizures in an open-label comparison with standard antiepileptic drug therapy (carbamazepine and valproate). No differences in cognitive tests were observed between oxcarbazepine and carbamazepine/valproate over a 6-month treatment period.

Global and regional volume changes in the brains of patients with phenylketonuria

Background: Although phenylketonuria is a treatable disease, patients with late or nonoptimal phenylalanine-restricted diet may experience brain damage. The authors used tridimensional MRI and a voxelwise analysis method to investigate possible volume changes in the brain parenchyma of patients with phenylketonuria.

Methods: The authors assessed 27 treated patients (mean age ± SD, 20 ± 7 years) and 27 matched control subjects. Global tissue volumes were compared, and statistical parametric maps of between-group regional volume differences were obtained for gray and white matter. Anatomic data were correlated with relevant clinical and biochemical variables.

Results: Patients with phenylketonuria showed smaller gray matter volumes that were associated with lower IQ and older age at diagnosis. Voxel-based maps revealed that significant gray matter volume reduction occurred in motor and premotor cortex and thalamus. A relative increase in gray matter volume was observed in the ventral part of the striatum. The authors found no group differences for global white matter measurements. Higher recent phenylalanine levels, however, were associated with larger global white matter volume in early-treated patients. Voxel-based maps showed a relative volume reduction in periventricular white matter and a relative increase in the region of the internal capsule, extending to the adjacent thalamus and striatum.

Conclusions: Treated patients may show significant gray and white matter volume changes related to the duration and strict observation of dietary treatment. Further studies are needed to investigate whether the presence of neurologic symptoms may be explained by specific anatomic alterations.

[Inborn errors of neurotransmitters in neuropaediatrics]

AIMS

The aim of this work is to describe the clinical, biochemical and genetic characteristics of neurotransmitter diseases at the paediatric age, together with possible forms of treatment. We also sought to determine the diagnostic methodology of these disorders (collection and analysis of samples).

DEVELOPMENT

These diseases essentially consist of a deficit of biogenic amines and alterations in GABA metabolism (gamma-aminobutyric acid). Disorders affecting the neurotransmission of biogenic amines often present in the form of hypokinesia, trunk hypotonia with increased limb tone, oculogyric crises, ptosis, faulty temperature regulation or abnormal movements. Defects in GABA metabolism give rise to epileptic encephalopathies and unspecific mental retardation, sometimes associated to signs of cerebellar dysfunction, convulsions and alterations in neuroimaging studies. Overall incidence of these diseases is low but they are unquestionably under-diagnosed, since they cannot be detected by conventional studies in plasma and urine, and require extraction and directed analysis of cerebrospinal fluid (CSF) for their detection. Additionally, the CSF study must be carried out in specific standardised conditions. Segawa's disease, or dopa-responsive dystonia, responds extremely well to therapy, whereas the other entities respond in varying ways to the different therapeutic alternatives.

CONCLUSIONS

It is important for the paediatrician to know about these entities as a group of treatable neurometabolic diseases. Moreover, their detection would allow prenatal diagnosis in the vast majority of cases.

[Encephalopathy with methylmalonic aciduria and homocystinuria secondary to a deficient exogenous supply of vitamin B12]

INTRODUCTION

A deficient supply of vitamin B12 can appear early during the first months of life, with haematological and neurological symptoms in the form of progressive encephalopathy.

CASE REPORTS

We describe two patients with megaloblastic anaemia and halted somatic and cranial perimeter development, accompanied by neurological involvement. Both of them had an increased rate of excretion of methylmalonic acid, as well as homocysteine, in urine with extremely low serum levels of vitamin B12, as compared to normal values. Both patients were breastfed only. The study of the mothers revealed asymptomatic pernicious anaemia. Treatment with hydroxycobalamine led to clinical recovery and psychomotor development progressively returned to normal.

CONCLUSIONS

Vitamin B12 deficiency due to a shortage of supply from the mother must be taken into account in the differential diagnosis of possibly reversible severe encephalopathies.

[Inborn errors of metabolism with neurological symptomathology in the neonatal period]

INTRODUCTION

Congenital metabolic diseases are considered as rare diseases because of their low incidence and their clinical symptoms at onset. Sometimes they can just begin in the neonatal period. Their progressive knowledge and the availability of specific and sensitive biochemical procedures allow us to diagnose many congenital metabolic diseases, which were not recognized some years ago.

PATIENTS AND METHODS

We reviewed the 52 patients with congenital metabolic diseases diagnosed for the last 25 years in our centre, evaluating the clinical presentation, neurological symptoms, complementary exams and clinical evolution.

RESULTS

The mean age at onset of symptoms was 5 days and the mean age at diagnosis was 88 days of age. We considered a first group of 36 patients with inborn errors of intermediary metabolism, in whom hypotonia, weight loss and seizures are the main symptoms. The second group was composed of 8 patients with defective energy metabolism, who showed abnormal respiratory rhythm and hypotonia. Finally, we considered 8 patients with diseases of the complex molecules, who presented with hypotonia and cataracts as common symptoms at onset. The more common neurological symptoms in this period were hypotonia (60%), sensorial deficit (35%) and refractory seizures (23%). The complementary laboratory tests in the first phases of the diseases allowed us to suspect a congenital metabolic disease especially among intermediary and energy defects. EEG registration and CSF samples were important to diagnose some inborn errors of intermediary metabolism. In the first steps, the neuroimaging was less orientative, even if it allow the exclusion of other diseases. More than half of the patients with inborn errors of metabolism with onset in the neonatal period died within the first year of life.

CONCLUSION

It is really important to suspect these diseases in the neonatal period so as to achieve an early diagnosis and therapy which may reduce the morbimortality.

Platelet serotonin concentrations in PKU patients under dietary control and tetrahydrobiopterin treatment

Tetrahydrobiopterin (BH4) supplementation has been applied in PKU treatment, resulting in successful control of blood phenylalanine (Phe) concentrations. We evaluated serotonin status in PKU patients under classical dietary treatment (n = 40) and in a group of 11 PKU patients under BH4 treatment, both during a 6-month period. Platelet serotonin values were significantly lower in PKU patients under dietary treatment when compared with controls. A negative correlation was observed between plasma Phe and platelet serotonin concentrations (r = -0.367, p = 0.017) in PKU patients. Platelet serotonin concentration increased significantly after both 1 and 6 months of BH4 therapy when compared with baseline conditions (Wilcoxon test: p = 0.013 and p = 0.021, respectively), while no differences were observed when comparing plasma Phe concentrations at the different points. Our results indicate that PKU patients under classical treatment have decreased platelet serotonin concentrations, probably owing to continued high Phe values, while BH4 supplementation restored platelet serotonin values.

[Pathogenetic mechanisms in phenylketonuria: disorders affecting the metabolism of neurotransmitters and the antioxidant system]

AIM

To review the clinical and biochemical changes in neurotransmission and antioxidant system in phenylketonuric patients under dietary treatment.

DEVELOPMENT

Phenylketonuria (PKU) is an inborn error of metabolism caused by decreased activity of the enzyme L-phenylalanine-4-mono-oxigenase that synthesizes tyrosine from phenylalanine. According to analytical data from PKU patients and to experimental studies in animal models, high phenylalanine values in plasma and tissues seem to be related with defective biosynthesis of neurotransmitter (mainly serotonin and dopamine) and impairment of antioxidant system. Despite dietary treatment, PKU patients usually present moderate hyperphenylalaninemia over the evolution of the disease that might cause clinical and biochemical abnormalities.

CONCLUSIONS

Increased plasma phenylalanine concentrations and dietary treatment might be related with neurotransmitter and antioxidant system abnormalities in human phenylketonuria. These biochemical alterations might be involved in the physiopathology of PKU.