Identification of SLC7A7, encoding y+LAT-1, as the lysinuric protein intolerance gene.

Lysinuric protein intolerance (LPI; OMIM 222700) is a rare, recessive disorder with a worldwide distribution, but with a high prevalence in the Finnish population; symptoms include failure to thrive, growth retardation, muscle hypotonia and hepatosplenomegaly. A defect in the plasma membrane transport of dibasic amino acids has been demonstrated at the baso-lateral membrane of epithelial cells in small intestine and in renal tubules and in plasma membrane of cultured skin fibroblasts from LPI patients. The gene causing LPI has been assigned by linkage analysis to 14q11-13. Here we report mutations in SLC7A7 cDNA (encoding y+L amino acid transporter-1, y+LAT-1), which expresses dibasic amino-acid transport activity and is located in the LPI region, in 31 Finnish LPI patients and 1 Spanish patient. The Finnish patients are homozygous for a founder missense mutation leading to a premature stop codon. The Spanish patient is a compound heterozygote with a missense mutation in one allele and a frameshift mutation in the other. The frameshift mutation generates a premature stop codon, eliminating the last one-third of the protein. The missense mutation abolishes y+LAT-1 amino-acid transport activity when co-expressed with the heavy chain of the cell-surface antigen 4F2 (4F2hc, also known as CD98) in Xenopus laevis oocytes. Our data establish that mutations in SLC7A7 cause LPI.

[A guide to the clinical diagnosis and urgent treatment of neonatal hyperammonaemia]. / Guía clínica de diagnóstico y tratamiento urgente de hiperamonemia neonatal.

Symptomatic hyperammonaemia in newborn is a medical emergency that should be recognised in its early stages, specifically diagnosed and aggressively treated to improve the immediate and long-term prognosis of these children. The paediatrician and the neonatal doctor should have a diagnosis-therapy scheme for its urgent management.

[Inborn errors of metabolism as rare diseases with a specific global situation]. / Los errores congénitos del metabolismo como enfermedades raras con un planteamiento global específico.

So-called congenital metabolic diseases (CMD) are a consequence of biochemical alterations originating in the genes that result in the alteration of a protein. Depending on this protein's function - whether as an enzyme, a hormone, a receiver-transporter of a cellular membrane or forming part of a cellular organelle (lysosome, peroxysome) - different groups of diseases emerge, which cause the most outstanding characteristic of inborn errors of metabolism (IEM): their clinical heterogeneity. The majority of these diseases are autosomal recessive, with a limited number of asymptomatic carriers, but there are also those ruled by an autonomous, dominant character inheritance or linked to the X chromosome. Taken individually, CMDs are highly infrequent, but taken as a whole CMDs (of which over 500 have been described to date) can affect 1/500 of the newborn. A common characteristic of many CMDs is the possibility of dietary treatment and treatment with enzymatic replacement. For essentially didactic purposes the following groups should be considered: CMDs of the intermediary metabolism (whose types are intoxication and energy deficit), CMDs of cellular organelles, complex CMDs due to cycle alterations and others. A summary is presented of the clinical, diagnostic and therapeutic aspects of one disease of each type of those previously described: hyperphenylalaninemias, deficiencies of the mitochondrial oxidative phosphorilation (OXPHOS) and lysosomal storage diseases.

[A randomized single-blind trial of the effects of vitamins C and E in familial hypercholesterolemia]. / Ensayo aleatorizado ciego-sencillo sobre los efectos de las vitaminas C y E en la hipercolesterolemia familiar.

INTRODUCTION: The aim of this study was to evaluate the effect of antioxidant vitamin C and E administration on dyslipidemia, plasma fatty acid composition, and biochemical inflammatory markers in children with heterozygous familial hypercholesterolemia (FH). PATIENTS: Forty girls and boys with heterozygous FH, aged between 2 and 18 years, and with plasma low-density lipoprotein (LDL)-cholesterol levels higher than 160 mg/dl were studied. METHODS: We performed an open longitudinal randomized trial over a 1-year period. All children followed a dietary intervention according to the National Cholesterol Education Program (NCEP)-1 guidelines and were randomized into two groups. One group (n = 21) received therapy with vitamin C (500 mg twice a day) and vitamin E (400 IU per day). A second group (n = 19) did not receive vitamin therapy. RESULTS: In patients receiving antioxidant vitamins, plasma linoleic acid levels (18:2 omega-6) significantly increased and the essential fatty acid deficiency ratio significantly decreased (Mead/arachidonic acid: 20:4 omega-6/20:3 omega-9). No significant differences were observed in plasma lipid profile, adhesion molecules, or reactive C protein. CONCLUSIONS: Antioxidant vitamin therapy in children with heterozygous FH modifies the plasma fatty acid profile. These modifications are independent of the degree of dyslipidemia and may represent an indicator of reduced cardiovascular risk.

Identification of a cytogenetic deletion and of four novel mutations (Q69X, I172F, G188V, G197R) affecting the gene for ornithine transcarbamylase (OTC) in Spanish patients with OTC deficiency.

A deletion of at least 11.5 cM in the paternal X chromosome mapping between microsatellites DXS989 and DXS1003 and encompassing the genes for ornithine transcarbamylase (OTC), retinitis pigmentosa GTPase regulator (RPGR) and dystrophin, was associated with the loss of band Xp21 in a female patient with OTC deficiency. Another four female patients were heterozygous for point mutations in the OTC gene: the nonsense mutation Q69X or the missense mutations I172F, G188V and G197R. In the OTC amino acid sequence, I172 and G197 are proximate to residues involved in catalysis, and G188 is within a loop joining helix 5 and strand 6 in the core of the ornithine-bindingdomain. Therefore, the mutations of these residues may cause structural changes affecting catalysis and/or the architecture of the ornithine domain. The mutation appeared "de novo" in the patients or, in one case, in the mother of the patient, in agreement with the predominance of "de novo" mutations in female patients of OTC deficiency. There was full agreement between the results of mutational analysis and of allopurinol testing in the patients and their female relatives, supporting the value of the allopurinol test in the detection of carriers of OTC deficiency. This deficiency is a genetically heterogeneous X-linked condition.

Relationship between mutation genotype and biochemical phenotype in a heterogeneous Spanish phenylketonuria population.

Genotyping of the phenylalanine hydroxylase (PAH) gene offers a new tool for characterizing patients with phenylketonuria (PKU), refining the diagnosis and aiding in the prediction of the clinical outcome and in the implementation of a more adequate treatment. The primary goal of this work was the detailed study of the different allele combinations and the metabolic phenotypes in Spanish PKU patients in order to understand better the clinical heterogeneity of PAH deficiency in our population. The results show that the disease phenotype is a consequence of a combination of mutations at the PAH locus and this observation is valid throughout the spectrum of clinical and biochemical varieties found in Spanish PKU patients. A stronger correlation was found between the predicted residual activity, when known from previous in vitro studies of the mutant proteins, and the Phe tolerance than between the predicted residual activity and the inverse of Phe levels at diagnosis. The observed genotype-phenotype correlations and the available data on the in vitro residual activity of the mutant proteins has enabled the estimation of the severity of most of the mutations found in Spain. This study includes relevant data for clinicians and pediatricians adding to the present knowledge which relates allelic PAH genotypes to biological phenotypes.

Genetic and phenotypic aspects of phenylalanine hydroxylase deficiency in Spain: molecular survey by regions.

We present an extensive study of the genetic diversity of phenylalanine hydroxylase deficiency in the Spanish phenylketonuria population. We have analysed 195 PKU patients by DGGE analysis identifying 67 different mutations which represent 89% of the total mutant chromosomes. Seventeen mutations first described in Spain have not yet been detected elsewhere; ten of these are reported here for the first time. The clinical significance of this high genetic heterogeneity was examined by analysing the genotype-phenotype correlations, mainly focusing on the mild hyperphenylalaninaemia (MHP) phenotype. The genotypes found in a group of 93 MHP patients, the largest analysed so far, are described in detail, as well as the relative frequencies of the MHP mutations identified. From the total pool of mutations, 27 can be considered severe, 18 can be defined as mild and 13 as associated with MHP. The prevalent mutations correspond to one severe mutation (IVS10nt-11), one MHP mutation (A403V) and two mild mutations (165T and V388M). The high frequency of mutations with a low degree of severity can explain the relatively higher prevalence of MHP and mild PKU phenotypes in Spain compared with NOrthern European populations. We have looked at the geographical distribution in Spain of the more common mutations, finding evidence of local mutation clustering, which could be the result of differences in the ethnic background and/or of genetic drift within each region.

Intrauterine growth retardation and plasma fatty acids in the mother and the fetus.

BACKGROUND: Assessing the relationship between plasma fatty acids, specially polyunsaturated fatty acids in the mother and the fetus and intrauterine growth retardation (IUGR) in an apparently well-nourished population. DESIGN: Case-control intrapartum analysis. SETTING: Academic tertiary hospital. PATIENTS, PARTICIPANTS: There were 17 IUGR newborn cases (23 mothers) and 34 newborn control cases (46 mothers). MAIN OUTCOME MEASURE: Eleven fatty acids were blindly analysed in plasma by means of gas chromatography. RESULTS: Percentage values of eicosapentaenoic acid among mothers from the IUGR group were significantly higher than controls, whereas stearic absolute values were significantly reduced. On the other hand there were no differences in percentage values nor in absolute values regarding the 11 fatty acids analysed in newborn infants. CONCLUSION: In an apparently well-nourished population IUGR is not associated with an alteration in plasma fatty acids on the fetal side. However, on the maternal side some imbalance in eicosapentaenoic and stearic acids were found which will require further study.

Intake of long chain w3 polyunsaturated fatty acids during pregnancy and the influence of levels in the mother on newborn levels.

OBJECTIVE: To assess the relationship between the free intake of long chain w3 polyunsaturated fatty acid (w3 LCP) during pregnancy and the levels in the mother with the levels in the neonate. DESIGN: Cross-sectional study. SETTING: University hospital. SUBJECTS: One hundred and sixty-two mother-neonate pairs from normal at-term pregnancies. MAIN OUTCOME MEASURE: Dietetic interview in order to assess the w3 LCP intake. w3 LCPs were analyzed by capillary gas chromatography in plasma (expressed as percentage and as total amount) and in erythrocyte phospholipids (expressed as percentage) from mothers and neonates. RESULTS: The w3 LCP intake assessed by the dietetic interview was significantly correlated with w3 LCP levels in the plasma of both mothers and neonates. The levels of w3 LCPs in mothers and neonates were significantly correlated both in plasma fatty acids (expressed both as a percentage and absolute values) and in erythrocyte phospholipids (in percentage) (r=0.49-0.22). CONCLUSION: In an apparently well-nourished population the w3 LCP levels of the newborn infants are clearly influenced by those of their mothers. The higher the levels in mothers, the higher those in the neonates. The w3 LCP intake assessed by an interview also showed a significant influence, but to a lesser extent.

Molecular analysis of hereditary hyperferritinemia-cataract syndrome in a large Basque family.

Hereditary hyperferritinemia-cataract syndrome is a genetic condition characterized by constitutively increased serum ferritin values in the absence of iron overload and by bilateral cataract. It has been demonstrated that mutations in the stem loop structure of the iron regulatory element (IRE) located in the 5'-untranslated region of the ferritin L-subunit gene (19q13.1) are responsible for the anomalous expression of this protein. Although not clearly explained, cataract formation seems secondary to the increased levels of ferritin in the lens. We analyzed a large Basque family in order to identify possible germline alterations of the iron regulatory element of the ferritin-L gene in affected individuals and first-degree relatives. All members of the family presented hyperferritinemia and cataract except a young child who had hyperferritinemia but did not present cataract. Sequence analysis permitted the identification of an A40-->G mutation in all members, including this child. This could demonstrate that cataract formation is a consequence of ferritin accumulation in the lens.

Biochemical markers of n-3 long chain polyunsaturated fatty acid intake during pregnancy.

BACKGROUND: To assess the relationship between the mothers' intake of n-3 long chain polyunsaturated fatty acids (LC PUFA) during pregnancy and their levels in plasma and tissue. METHODS: 162 mothers were studied during labor. Three groups were differentiated according to the n3 LC PUFA intake assessed by means of a dietetic interview: superior intake (SIG) (> 0.721 g/day), medium intake (MIG) (from 0.382 to 0.721 g/day) and inferior intake (IIG) (< 0.381 g/day). Fatty acids (FA) were studied by capillary chromatography in plasma and in erythrocyte phospholipids. RESULTS: The fatty acids (FA), expressed in absolute values, did not show any significant differences among the aforementioned groups. However, three were some trends which were confirmed when the FA were expressed in percentages. Thus, higher levels of docosahexaenoic acid (DHA) were found in SIG both in plasma and in the erythrocyte membrane, when expressed in percentages. Eicosapentaenoic acid (EPA) was also higher in the SIG in the erythrocyte membrane, whereas in plasma the differences were of marginal significance. On the other hand, arachidonic and linoleic acids had lower values in the SIG in erythrocytes. The theoretical optimal intake of n-3 LC PUFA corresponded to a plasma concentration of 117.9 +/- 45.9 mcg/ml n-3 LC PUFA or 2.54% of the total fatty content (2.29% of DHA). The corresponding cut-offs in erythrocyte membranes were 7.54% of total lipids (5.59% of DHA). CONCLUSION: The best markers of n-3 LC PUFA intake were DHA for plasma and DHA and EPA for erythrocyte phospholipids, all of them expressed in proportions of total FA. The arachidonic and linoleic acids (in percentages) in erythrocyte phospholipids were also good markers of n-3 intake. This probably reflects the metabolic competition between both PUFA families.

[Tissue antioxidant capacity and bacterial translocation in parenteral nutrition. Experimental study]. / Capacidad antioxidante tisular y traslocación bacteriana bajo nutrición parenteral. Estudio experimental.

Alterations in the antioxidant system (AS) has been observed during total parenteral nutrition (TPN). Light exposure or changes in the composition of TPN may affect this deleterious effect. On the other hand, bacterial translocation (BT) is frequent under TPN and may be related to AS. The aim of the study was to determine the adverse effect of standard and glutamine-enriched (GE) TPN, with or without light exposure, on the AS, and its relationship to BT. Forty-nine adult Wistar rats underwent central venous cannulation and were randomly assigned to one of five groups: Sham (n = 16): chow and water ad libitum and saline i.v. TPN (n = 10): had standard TPN. TPN(-) (n = 8): standard TPN without light-exposure. GTPN (n = 8): GE TPN. GTPN(-) (n = 7): GE TPN without light exposure. After 10 days, glutation reduced (GSH) was determined in liver and kidney. Mesenteric lymph nodes, peripheral and portal blood samples were cultured for BT. Comparing to Sham rats, TPN groups had statistically significant lower GSH levels, but there were no differences between standard or GE groups nor with or without light exposure groups. Sham animals had 12% BT. Significantly higher BT (p < 0.05) was found in TPN rats: 70% in TPN group, 88% in TPN(-) group, 86% in GTPN(-) animals and only 50% in GTPN group (p = 0.06 vs TPN group). To conclude: 1. TPN reduces antioxidant capacity and induces BT. 2. Glutamine supplementation or light protection do not improve tissue antioxidant capacity under TPN. 3. Glutamine supplementation tends to reduce BT only in the presence of light. 4. Absence of light exposure does not improve BT TPN-related.

Recomendaciones para el diagnóstico y el tratamiento de la enfermedad de Gaucher durante la infancia / Recommendations for diagnosis and treatment of pediatric Gaucher disease

El diagnóstico y el tratamiento de la enfermedad de Gaucher infantil presentan dificultades debido a su variabilidad clínica. Tres pediatras expertos en la enfermedad han propuesto una serie de recomendaciones generales al respecto. El paciente debe ser asistido por un equipo multidisciplinario, en un centro pediátrico con experiencia en el tratamiento de enfermedades metabólicas. El diagnóstico del paciente sintomático se garantiza con la anamnesis, el examen físico (afectación visceral, hematológica, esquelética y/o del sistema nervioso central), los exámenes complementarios y la confirmación mediante un estudio enzimático y genético. Los objetivos terapéuticos son recuperar al paciente de los síntomas que presenta, modificar beneficiosamente la evolución natural de la enfermedad y evitar el desarrollo de asociaciones patológicas. En los pacientes sin patología neurológica menores de 20 años de edad es obligado el tratamiento enzimático sustitutivo i.v., pero en patología neurológica no ejerce efecto sobre el sistema nervioso central, aunque puede utilizarse en la forma tipo III para mejorar las manifestaciones viscerales y óseas (AU)

The diagnosis and treatment of pediatric Gaucher disease is difficult due to its clinical variability. Three pediatricians, experts in the disease, have proposed a series of recommendations regarding the subject. The patient must be taken care of by a multidisciplinary team, in a pediatric center with experience in metabolic diseases. The diagnosis of the symptomatic patient is guaranteed by the anamnesis, physical exam (visceral, hematologic, skeletal and/or CNS involvement), complementary exams and confirmation by means of enzymatic and genetic studies. The therapeutic objectives are recovery from exhibited symptoms, beneficial modification of the natural course of the disease and avoidance of development of associated pathology. In patients with no neurologic pathology <20 years old, iv enzymatic replacement therapy is mandatory but in case of neurologic pathology it does not exert an effect on SNC, although it may be used in type III to improve visceral and bone manifestations (AU)

Effect of docosahexaenoic acid administration on plasma lipid profile and metabolic parameters of children with methylmalonic acidaemia.

AIM: To evaluate the effect of administration of docosahexaenoic acid (DHA) on dyslipidaemia, plasma fatty acid composition and metabolic parameters of children with isolated methylmalonic acidaemia (MMA) (McKusick 25100). METHODS: Four children (3 male, 1 female) with MMA (mut(0)), participated in a crossover, randomized study of DHA administration (25 mg/kg per day, divided into three daily doses). The control group comprised 56 healthy children, aged 10+/- 2.7 years, (51 male, 5 female), who were followed in our clinic owing to possible familial risk of cardiovascular disease. RESULTS: The comparison of plasma fatty acid composition of children with MMA versus control children demonstrated that the patients had significantly higher values for oleic acid (p = 0.004) and linolenic acid (p = 0.008). No differences were observed in the levels of DHA and arachidonic acid. Plasma concentrations of insulin, glycine, ammonia, total cholesterol and cholesterol fractions did not change with DHA administration. No significant changes were observed in urinary excretion of methylmalonic acid. As expected, the percentage of DHA and n-3 fatty acids in plasma increased significantly after therapy (p = 0.005 and 0.014, respectively). The most remarkable result was a decrease of plasma levels of triglycerides after DHA therapy (p = 0.014). CONCLUSION: As previously found in normal children, dietary supplementation with DHA decreases the triglyceride levels, normalizing the hypertriglyceridaemia of these children without any evidence of short-term adverse effects.

[Changes in cholesterol esterification ratio during parenteral feeding including lipids (author's transl)]. / Alteraciones del índice de esterificación del colesterol a lo largo de la alimentación parenteral.

Authors report the finding of an important change in the esterification of plasma cholesterol during parenteral nutrition using 10% intralipid. Thirty-seven patients with various disorders were included in the study. The results and possibility of deleterious effects are discussed.

[Lecithin /sphingomyelin ratio and palmitic acid percentage in the diagnosis and prediction of idiopathic respiratory distress syndrome]. / Relación lecitina/esfingomielina y porcentaje de palmítico en el diagnóstico y la predicción del síndrome de distress respiratorio idiopático (SDRI).

The L/S ratio of gastric aspirate was determined in the first day of life in 47 patients with IRDS and in 87 without IRDS. In 97.7% of those without IRDS the gastric L/S ratio was greater than 3.5. Ninety three percent (93%) of the patients with IRDS had a gastric L/S ratio less than 3.5. In these cases the palmitic percentage was 49.1 +/- 11.5 been in normal full term infants 69.4 +/- 5.2 (p less than 0.01). The use of a biochemical score including the L/S ratio and the palmitic acid percentage in patients with IRDS could differentiate survivors and non survivors.

Influence of fatty fish intake during pregnancy in the polyunsaturated fatty acids of erythrocyte phospholipids in the mother at labor and newborn infant.

BACKGROUND: Assessing the relationship between fatty fish intake, the main source of N-3 polyunsaturated fatty acids and maternal and fetal levels in erythrocytes at labor. METHODS: The fatty acid composition was studied in 64 mother-newborn infant pairs by means of capillar gas chromatography. Following a nutritional inquiry our population was classified as follows: superior intake group (SIG) (> 4 times fatty fish per month; 54.4 +/- 20.5 g/day), medium intake group (MIG) (2-4 per month; 16.5 +/- 4 g/day) and inferior intake group (IIG) (< 2 times per month; 4.3 +/- 4 g/day). RESULTS: In erythrocyte phospholipids higher levels were observed in SIG in relation to IIG in mothers regarding eicosapentaenoic (0.56 +/- 0.3% and 0.39 +/- 0.2%; p = 0.02) and docosahexaenoic acids (6.14 +/- 1.16% and 5.4 +/- 0.98%; p = 0.02) and in newborn infants regarding eicosapentaenoic acid (0.32 +/- 0.24% and 0.17 +/- 0.09%; p < 0.01). On the other hand, SIG had lower values of arachidonic acid than IIG in mother (11.15 +/- 1.61% vs 12.83 +/- 1.86%; p < 0.01) and newborn infants (16.08 +/- 3.42% vs 17.89 +/- 2.57%; p = 0.05). CONCLUSIONS: From a biochemical point of view, and taking into account the pre-existing literature, it is suggested that a minimum fatty fish intake of twice per month should be recommended (edible portion 85 g.) in order to reach the N-6/N-3 quotient usually proposed.

[Physiopathology of idiopathic respiratory distress syndrome (author's transl)]. / Fisiopatología del síndrome de dificultad respiratoria idiopática

Physiopathology of idiopathic respiratory distress syndrome is reviewed and bases for a correct management are given. Special mention is made of pulmonary surfactant system, biosynthesis of surfoactive material and techniques used to predict appearance of pulmonary maturity.