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Background: Dyslipidaemia represents a group of disorders of lipid metabolism, characterized by either an increase or decrease in lipid particles, usually associated with triglycerides, LDL cholesterol (LDL-C) and/or HDL cholesterol (HDL-C). Most hyperlipidaemias and HDL deficiencies confer an increased cardiovascular risk, while hypolipidaemia, such as abeta or hypobetalipoproteinemia, may present different manifestations ranging from poor weight progression to neurological manifestations. The aim of this study is to present 7 cases with rare dyslipidaemias associated with low LDL or low HDL cholesterol values, referred to our laboratory for the genetic identification of the cause of the dyslipidaemia.Methods: Lipid profile was determined for each individual in an automated equipment Integra Cobas (Roche). Molecular analysis was performed by NGS with a target panel of 57 genes involved in lipid metabolism (Sure select QXT, Agilent) and samples were run in a NextSEQ Sequencer (Illumina). Only genes associated to rare forms of low HDL-c or LDL-c were analysed for this work, namely: ABCA1, APOA1, LCAT, SCARB1, APOB, PCSK9, MTTP, SAR1B, and ANGPTL3. All rare variants (MAFResults and discussion: This study includes 7 index cases (IC), with the following clinical diagnoses: Fish Eye Disease (1), Hypoalphalipoproteinemia (1) and Abetalipoproteinemia (ABL) / Familial Hypobetalipoproteinemia (FHBL) (5). We have identified one IC with a compound heterozygosity in LCAT causing Fish Eye Disease and one IC with a variant in ABCA1 in homozygosity causing Tangier disease. We found variants causing homozygous FHBL in 2 IC, one of whom has an undescribed pathogenic variant in homozygosity in APOB (c.12087+1G>A) and the other is a possible compound heterozygous for APOB variants c.2604+1G>A and c.4651C>T/p.(Gln1551*). In two patients only a variant in heterozygosity (c.3365delG/p.(Gly1122Vfs*62) and c.11095A>T/p.(Arg3699*)). In the remaining patient, no variants were identified. NGS proved to be a fundamental key for genetic testing of rare lipid disorders, allowing us to find the genetic cause of disease in 6/7 patients with low HDL-c and LDL-c. Patients with these rare conditions should be identified as early as possible in order to minimize or prevent clinical manifestations. The unsolved case is still under investigation.

OBJECTIVE: To describe the clinical, biochemical, and genetic features of both new and previously reported patients with congenital disorders of glycosylation (CDGs) diagnosed in Portugal over the last 20 years. STUDY DESIGN: The cohort includes patients with an unexplained multisystem or single organ involvement, with or without psychomotor disability. Serum sialotransferrin isoforms and, whenever necessary, apolipoprotein CIII isoforms and glycan structures were analyzed. Additional studies included measurement of phosphomannomutase (PMM) activity and analysis of lipid-linked oligosaccharides in fibroblasts. Sanger sequencing and massive parallel sequencing were used to identify causal variants or the affected gene, respectively. RESULTS: Sixty-three individuals were diagnosed covering 14 distinct CDGs; 43 patients diagnosed postnatally revealed a type 1, 14 a type 2, and 2 a normal pattern on serum transferrin isoelectrofocusing. The latter patients were identified by whole exome sequencing. Nine of them presented also a hypoglycosylation pattern on apolipoprotein CIII isoelectrofocusing, pointing to an associated O-glycosylation defect. Most of the patients (62%) are PMM2-CDG and the remaining carry pathogenic variants in ALG1, ATP6AP1, ATP6AP2, ATP6V0A2, CCDC115, COG1, COG4, DPAGT1, MAN1B1, SLC35A2, SRD5A3, RFT1, or PGM1. CONCLUSIONS: Portuguese patients with CDGs are presented in this report, some of them showing unique clinical phenotypes. Among the 14 genes mutated in Portuguese individuals, 8 are shared with a previously reported Spanish cohort. However, regarding the mutational spectrum of PMM2-CDG, the most frequent CDG, a striking similarity between the 2 populations was found, as only 1 mutated allele found in the Portuguese group has not been reported in Spain. ispartof: JOURNAL OF PEDIATRICS vol:231 pages:148-156 ispartof: location:United States status: published

Background The pyruvate dehydrogenase complex (PDC) catalyzes the irreversible decarboxylation of pyruvate into acetyl-CoA. PDC deficiency can be caused by alterations in any of the genes encoding its several subunits. The resulting phenotype, though very heterogeneous, mainly affects the central nervous system. The aim of this study is to describe and discuss the clinical, biochemical and genotypic information from thirteen PDC deficient patients, thus seeking to establish possible genotype–phenotype correlations. Results The mutational spectrum showed that seven patients carry mutations in the PDHA1 gene encoding the E1α subunit, five patients carry mutations in the PDHX gene encoding the E3 binding protein, and the remaining patient carries mutations in the DLD gene encoding the E3 subunit. These data corroborate earlier reports describing PDHA1 mutations as the predominant cause of PDC deficiency but also reveal a notable prevalence of PDHX mutations among Portuguese patients, most of them carrying what seems to be a private mutation (p.R284X). The biochemical analyses revealed high lactate and pyruvate plasma levels whereas the lactate/pyruvate ratio was below 16; enzymatic activities, when compared to control values, indicated to be independent from the genotype and ranged from 8.5% to 30%, the latter being considered a cut-off value for primary PDC deficiency. Concerning the clinical features, all patients displayed psychomotor retardation/developmental delay, the severity of which seems to correlate with the type and localization of the mutation carried by the patient. The therapeutic options essentially include the administration of a ketogenic diet and supplementation with thiamine, although arginine aspartate intake revealed to be beneficial in some patients. Moreover, in silico analysis of the missense mutations present in this PDC deficient population allowed to envisage the molecular mechanism underlying these pathogenic variants. Conclusion The identification of the disease-causing mutations, together with the functional and structural characterization of the mutant protein variants, allow to obtain an insight on the severity of the clinical phenotype and the selection of the most appropriate therapy.

Next-generation sequencing (NGS) technologies have been proposed as a first-line test for the diagnosis of inborn errors of metabolism (IEM), a group of genetically heterogeneous disorders with overlapping or nonspecific phenotypes. Over a 3-year period, we prospectively analyzed 311 pediatric patients with a suspected IEM using four targeted gene panels. The rate of positive diagnosis was 61.86% for intermediary metabolism defects, 32.84% for complex molecular defects, 19% for hypoglycemic/hyperglycemic events, and 17% for mitochondrial diseases, and a conclusive molecular diagnosis was established in 2-4 weeks. Forty-one patients for whom negative results were obtained with the mitochondrial diseases panel underwent subsequent analyses using the NeuroSeq panel, which groups all genes from the individual panels together with genes associated with neurological disorders (1870 genes in total). This achieved a diagnostic rate of 32%. We next evaluated the utility of a tool, Phenomizer, for differential diagnosis, and established a correlation between phenotype and molecular findings in 39.3% of patients. Finally, we evaluated the mutational architecture of the genes analyzed by determining z-scores, loss-of-function observed/expected upper bound fraction (LOEUF), and haploinsufficiency (HI) scores. In summary, targeted gene panels for specific groups of IEMs enabled rapid and effective diagnosis, which is critical for the therapeutic management of IEM patients. info:eu-repo/semantics/publishedVersion

Background The impairment of the hepatic enzyme phenylalanine hydroxylase (PAH) causes elevation of phenylalanine levels in blood and other body fluids resulting in the most common inborn error of amino acid metabolism (phenylketonuria). Persistently high levels of phenylalanine lead to irreversible damage to the nervous system. Therefore, early diagnosis of the affected individuals is important, as it can prevent clinical manifestations of the disease. Methods In this report, the biochemical and genetic findings performed in 223 patients diagnosed through the Portuguese Neonatal Screening Program (PNSP) are presented. Results Overall, the results show that a high overlap exists between different types of variants and phenylalanine levels. Molecular analyses reveal a wide mutational spectrum in our population with a total of 56 previously reported variants, most of them found in compound heterozygosity (74% of the patients). Intragenic polymorphic markers were used to assess the haplotypic structure of mutated chromosomes for the most frequent variants found in homozygosity in our population (p.Ile65Thr, p.Arg158Gln, p.Leu249Phe, p.Arg261Gln, p.Val388Met, and c.1066‐11G>A). Conclusion Our data reveal high heterogeneity at the biochemical and molecular levels and are expected to provide a better understanding of the molecular basis of this disease and to provide clues to elucidate genotype–phenotype correlations., The present study identify and characterize the variants underlying PKU in affected individuals in the Portuguese PKU/HPA cohort. Biochemical data, haplotic analysis and genetic findings performed in 223 patients diagnosed through the Portuguese Neonatal Screening Program (PNSP) is presented. The information obtained will improve the diagnostic applicability of mutational analysis and the capacity to predict the evolution of the disease.

Hyperammonemia can be a potentially fatal disorder, secondary to several different etiologies, most commonly urea cycle defects and organic acidurias. The deficiency of mitochondrial carbonic anhydrase VA, a recently recognized metabolic disorder, results from abnormalities in the CA5A gene. This gene plays an important role in ureagenesis and gluconeogenesis, resulting in a secondary deficiency of several carboxylases and presenting as neonatal hyperammonemic encephalopathy. We describe the case of an almost 5-year-old child who had neonatal encephalopathy secondary to hyperammonemia wherein carbonic anhydrase VA deficiency was identified in him. His growth and development are normal despite no diet or medication for several years. We report this case as fewer than 20 patients have been described in the literature. info:eu-repo/semantics/publishedVersion

Familial Hypercholesterolemia (FH) is a common genetic hypercholesterolemia caused by mutations in LDLR, APOB and PCSK9 that leads to premature atherosclerosis. Other rare disorders like sitosterolemia can present the same phenotype but have distinct therapeutic interventions. We present a case of severe hypercholesterolemia in a 5-year-old child found to have both FH and sitosterolemia. The proband was diagnosed initially as FH, but the lack of pathogenic variants with Sanger approach questioned this hypothesis. High levels of sitosterol established the diagnosis of sitosterolemia, genetically confirmed by an ABCG8 homozygous variant c.1974C>G/p.(Tyr658*). NGS re-sequence for FH genes revealed an APOB heterozygous functional variant (c.11477C>T/p.(Thr3826Met), in a region previously unstudied. The mother presented the same genotype. Control of LDL-C levels was only accomplished with dietary and therapeutic intervention for both sitosterolemia and FH. The correct diagnosis of dyslipidemia is important to establish proper dietary and pharmacological intervention for atherosclerosis prevention., Portuguese Journal of Pediatrics, Vol. 52 No. 4 (2021)

3-MEthylGlutaconic aciduria, Deafness, Encephalopathy, neuroradiological evidence of Leigh-like disease (MEGDEL syndrome) was initially described in four children with additional features of defective oxidative phosphorylation. Loss of functional variants in the SERAC1 gene was later reported in relation with this disorder of phospholipid remodeling. We describe a girl born after a pregnancy complicated by intrauterine growth retardation. In the neonatal period, she presented hypotonia, lethargy, weak reflexes, transient hypoglycemia, and elevated transaminases. Magnetic resonance imaging (MRI) performed at 12 days of life showed bilateral basal ganglia alterations suggestive of Leigh syndrome. She progressed with failure to thrive, severe delay of developmental milestones, axial hypotonia, spastic tetraparesis and dystonic movements. Investigations disclosed hyperlactacidemia, and the urinary organic acids revealed high levels mainly of 3-methylglutaconic acid. Muscle biopsy showed decreased activity of several complexes of the respiratory chain. Compound heterozygosity for two previously unreported variants in SERAC1 leads to the diagnosis of MEGDEL syndrome. Unlike other patients, this child presents very early MRI alterations and manifests no deafness.

Free PMC Article: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5886929/ Thrombotic microangiopathy (TMA) syndromes can be secondary to a multitude of different diseases. Most can be identified with a systematic approach and, when excluded, TMA is generally attributed to a dysregulation in the activity of the complement alternative pathways-atypical hemolytic uremic syndrome (aHUS). We present a challenging case of a 19-year-old woman who presented with thrombotic microangiopathy, which was found to be caused by methylmalonic acidemia and homocystinuria, a rare vitamin B12 metabolism deficiency. To our knowledge, this is the first time that an adult-onset methylmalonic acidemia and homocystinuria presents as TMA preceding CNS involvement. info:eu-repo/semantics/publishedVersion

Selenium-binding protein 1 (SELENBP1) has been associated with several cancers, although its exact role is unknown. We show that SELENBP1 is a methanethiol oxidase (MTO), related to the MTO in methylotrophic bacteria, that converts methanethiol to H2O2, formaldehyde, and H2S, an activity not previously known to exist in humans. We identified mutations in SELENBP1 in five patients with cabbage-like breath odor. The malodor was attributable to high levels of methanethiol and dimethylsulfide, the main odorous compounds in their breath. Elevated urinary excretion of dimethylsulfoxide was associated with MTO deficiency. Patient fibroblasts had low SELENBP1 protein levels and were deficient in MTO enzymatic activity; these effects were reversed by lentivirus-mediated expression of wild-type SELENBP1. Selenbp1-knockout mice showed biochemical characteristics similar to those in humans. Our data reveal a potentially frequent inborn error of metabolism that results from MTO deficiency and leads to a malodor syndrome. info:eu-repo/semantics/publishedVersion

Lately, microdeletions of the 22q region, responsible for DiGeorge syndrome or velocardiofacial syndrome, have been increasingly related to neuropsychiatric disorders including schizophrenia and bipolar disorder. These manifestations seem to be related to certain genes located in the hemideleted region such as the proline dehydrogenase (PRODH) and the catechol-o-methyltransferase (COMT) genes. We describe a teenager who started his adolescent psychiatric care presenting cognitive impairment, irritable mood and aggressive behaviour with schizophrenia-like symptoms that scored 153 in the Positive and Negative Symptoms Scale (PANSS) assessment. Worsening of symptoms when the patient was treated with valproic acid, and plasma aminoacids showing an increase in alanine and proline, suggested a mitochondrial involvement of the proline metabolic pathway. Mild dysmorphic features also suggested a possible 22q11 deletion syndrome that was confirmed. A mutation for Hyperprolinemia type I was also detected. Knowledge of the correct diagnosis was crucial for an adequate treatment. info:eu-repo/semantics/publishedVersion

Introduction: Sulfite oxidase deficiency (SOD) is an autosomal recessive inherited disease usually presenting in the neonatal period with severe neurological symptoms including seizures, often refractory to anticonvulsant therapy, and a rapidly progressive encephalopathy resembling neonatal hypoxic ischemia, with premature death. Most patients develop dislocated ocular lenses. Later or milder presentations of SOD are being reported with increasing frequency. These presentations include neurological regression with loss of previously acquired milestones or movement disorders. Case report: We report a four years old girl presenting with intermittent ataxia and uncoordinated limb movements. A similar episode of ataxia had occurred previously, one year before, with complete neurologic recovery and normal developmental milestones. Bilateral lens dislocation had been recently diagnosed. Cranial MRI demonstrated bilateral globus pallidus enhancement. Low homocysteine was found in plasma and Sulfitest R was positive. Further investigations led to confirmation of isolated sulfite oxidase deficiency with no enzyme activity detected on skin fibroblasts culture. Discussion: This case illustrates the clinical variability of SOD and it is not only atypical but also seems to be the mildest form described so far. The association of ectopia lentis with a movement disorder, even without psychomotor regression, should prompt us to look for this diagnosis.

WOS: 000418389700017, PubMed ID: 29205472, Objective3-Methylglutaconic aciduria, dystonia-deafness, hepatopathy, encephalopathy, Leigh-like syndrome (MEGDHEL) syndrome is caused by biallelic variants in SERAC1. MethodsThis multicenter study addressed the course of disease for each organ system. Metabolic, neuroradiological, and genetic findings are reported. ResultsSixty-seven individuals (39 previously unreported) from 59 families were included (age range=5 days-33.4 years, median age=9 years). A total of 41 different SERAC1 variants were identified, including 20 that have not been reported before. With the exception of 2 families with a milder phenotype, all affected individuals showed a strikingly homogeneous phenotype and time course. Severe, reversible neonatal liver dysfunction and hypoglycemia were seen in >40% of all cases. Starting at a median age of 6 months, muscular hypotonia (91%) was seen, followed by progressive spasticity (82%, median onset=15 months) and dystonia (82%, 18 months). The majority of affected individuals never learned to walk (68%). Seventy-nine percent suffered hearing loss, 58% never learned to speak, and nearly all had significant intellectual disability (88%). Magnetic resonance imaging features were accordingly homogenous, with bilateral basal ganglia involvement (98%); the characteristic putaminal eye was seen in 53%. The urinary marker 3-methylglutaconic aciduria was present in virtually all patients (98%). Supportive treatment focused on spasticity and drooling, and was effective in the individuals treated; hearing aids or cochlear implants did not improve communication skills. InterpretationMEGDHEL syndrome is a progressive deafness-dystonia syndrome with frequent and reversible neonatal liver involvement and a strikingly homogenous course of disease. Ann Neurol 2017;82:1004-1015, Else Kroner-Fresenius Stiftung; German Bundesministerium fur Bildung und Forschung (BMBF)Federal Ministry of Education & Research (BMBF); Horizon2020 through the E-Rare project GENOMIT [01GM1603, 01GM1207, FWF I 2741-B26]; Vereinigung zur Forderung Padiatrischer Forschung und Fortbildung Salzburg; Wellcome Centre for Mitochondrial Research [203105/Z/16/Z]; Medical Research Council (MRC) Centre for Translational Research in Neuromuscular Disease, Mitochondrial Disease Patient Cohort (UK)Medical Research Council UK (MRC) [G0800674]; Lily Foundation; UK NHS Highly Specialised Service for Rare Mitochondrial Disorders of Adults and Children, M.S. was supported by the Else Kroner-Fresenius Stiftung" This study was supported by the German Bundesministerium fur Bildung und Forschung (BMBF) and Horizon2020 through the E-Rare project GENOMIT (01GM1603 and 01GM1207 for HP and FWF I 2741-B26 for J.A.M. J.A.M., S.B.W., W.S. were supported by the Vereinigung zur Forderung Padiatrischer Forschung und Fortbildung Salzburg. R.W.T. was supported by the Wellcome Centre for Mitochondrial Research (203105/Z/16/Z), the Medical Research Council (MRC) Centre for Translational Research in Neuromuscular Disease, Mitochondrial Disease Patient Cohort (UK) (G0800674), the Lily Foundation and the UK NHS Highly Specialised Service for Rare Mitochondrial Disorders of Adults and Children.

Hereditary spastic paraplegias (HSPs) are a group of rare inherited neurodegenerative disorders that result from primary retrograde dysfunction of the long descending fibers of the corticospinal tract, causing lower limb spasticity and muscular weakness. This group of diseases has a heterogeneous clinical presentation. An extensive list of associated genes, different inheritance patterns, and ages at onset have been reported in HSPs.1 Spastic paraplegia type 52 (SPG52) is an autosomal recessive disease caused by AP4S1 mutations. The disease is characterized by neonatal hypotonia that progresses to hypertonia and spasticity in early childhood, developmental delay, mental retardation, and poor or absent speech. Febrile or afebrile seizures may also occur.2–4 The authors acknowledge the family who participated in this study.

We report a case of hereditary fructose intolerance (HFI) with clinical onset prior to beikost: A two-month-old infant who had a first symptomatic hypoglycemic episode (generalized motor epileptic crisis) during a febrile respiratory infection with dyspnoea, while medicated with clarithromycin and betamethasone oral formulations. At nine months he presented a new hypoglycemic episode two hours after eating a flavored yogurt. The hepatomegaly and laboratory findings suggested the diagnosis of Von Gierke’s disease, not confirmed by molecular studies. There after, mother reported repeated vomiting episodes two hours after the ingestion of certain foods, leading to the clinical suspicion of HFI, subsequently confirmed by genetic analysis. There are few cases reporting metabolic decompensation of HFI prior to complementary feeding, mainly in exclusively breastfed children. We concluded that some routine formulations have excipients that can precipitate metabolic decompensation in HFI., Portuguese Journal of Pediatrics, Vol. 46 No. 3 (2015)

A hiperglicinémia não cetótica é um erro inato da degradação da glicina, resultando na sua excessiva acumulação nos tecidos corporais, designadamente no sistema nervoso central. Trata-se de uma doença muito grave e uma das terapêuticas recentemente propostas consiste na associação do dextrometorfano com o benzoato de sódio em altas doses. Admite-se a possibilidade de o dextrometorfano bloquear o complexo-canal receptor de N-metil-D-aspartato, implicado na toxicidade da hiperglicinémia ao nível do cérebro e de o benzoato reduzir os níveis de glicina, pela sua conjugação e eliminação como hipurato. Relatamos dois casos clínicos de crianças com hiperglicinémia não cetótita, actualmente com mais de 15 meses de idade, as quais foram medicadas com dextrometorfano e benzoato de sódio desde as primeiras semanas após o parto. Não obstante se ter verificado sobrevivência para além do período neonatal e aquisição de autonomia respiratória, a evolução neurológica, até à data, não tem sido satisfatória, porventura devido ao atraso no início da terapêutica., Portuguese Journal of Pediatrics, Vol 31 No 3 (2000)

Resumo: As doenças do ciclo da ureia são o resultado do défice enzimático de uma das enzimas que compõem a via metabó lica de excreção do azoto. Com a excepção do défice na transcarbamilase da ornitina, que está ligado ao cromos soma X, todas as doenças são autossómicas recessivas. A apresentação clínica destas doenças pode ocorrer no período neonatal, durante a infância ou mesmo na adolescência ou idade adulta. A hiperamoniemia, as alterações urinárias e plasmáticas dos aminoácidos e ácidos orgânicos, constituem os principais marcadores bioquímicos das doenças do ciclo da ureia. O tratamento nutricional baseia-se na implementação de uma dieta restrita em proteína natural e suplementada com uma mistura de aminoácidos essenciais. O aporte proteico tem de ser constantemente ajustado em função do controlo metabólico, da avaliação antropo métrica e da medicação usada para explorar as vias alternativas de excreção do azoto. A monitorização do estado nutricional assume uma importância crucial no seguimento destes doentes, de modo a melhor aferir as suas reais necessidades, prevenindo a insuficiência proteica, a qual poderá afectar negativamente o crescimento e desenvolvimento., Portuguese Journal of Pediatrics, vol. 40 n.º 4 (2009)

A síndrome de Smith-Lemli-Opitz (SLOS) é uma síndrome polimalformativa de transmissão autossómica recessiva causada por um défice metabólico da biossíntese do colesterol, que se caracteriza por dismorfias craniofaciais, anomalias congénitas de vários órgãos (salientando-se as do esqueleto e do aparelho urogenital), restrição de crescimento intra-uterino (RCIU), alterações comportamentais e atraso mental. É causada por mutações no gene DHCR7, que codifica para a enzima 7-dehidrocolesterol reductase, responsável pelo último passo da via metabólica da síntese do colesterol. A SLOS caracteriza-se por níveis diminuídos de colesterol e concentrações altas do seu precursor, 7-dehidrocolesterol, no sangue e tecidos. Procedeu-se a uma análise comparativa dos fenótipo e genótipo de quinze casos de SLOS de origem portuguesa, e são tecidas considerações quanto às dificuldades e limitações inerentes ao diagnóstico, e ao facto de esta doença hereditária do metabolismo dever ser considerada no diagnóstico diferencial das situações de (i) hipocolesterolémia, (ii) RCIU e (iii) síndromes polimalformativas, (especialmente quando crianças com atraso de crescimento apresentam simultaneamente sindactilia do segundo e terceiro dedos do pé e microcefalia e/ou narinas antevertidas entre outras anomalias)., Portuguese Journal of Pediatrics, vol. 43 n.º 2 (2012)

A síndrome de Smith-Lemli-Opitz (SLOS) é uma síndrome polimalformativa de transmissão autossómica recessiva causada por um défice metabólico da biossíntese do colesterol, que se caracteriza por dismorfias craniofaciais, anomalias congénitas de vários órgãos (salientando-se as do esqueleto e do aparelho urogenital), restrição de crescimento intra-uterino (RCIU), alterações comportamentais e atraso mental. É causada por mutações no gene DHCR7, que codifica para a enzima 7-dehidrocolesterol reductase, responsável pelo último passo da via metabólica da síntese do colesterol. A SLOS caracteriza-se por níveis diminuídos de colesterol e concentrações altas do seu precursor, 7-dehidrocolesterol, no sangue e tecidos. Procedeu-se a uma análise comparativa dos fenótipo e genótipo de quinze casos de SLOS de origem portuguesa, e são tecidas considerações quanto às dificuldades e limitações inerentes ao diagnóstico, e ao facto de esta doença hereditária do metabolismo dever ser considerada no diagnóstico diferencial das situações de (i) hipocolesterolémia, (ii) RCIU e (iii) síndromes polimalformativas,(especialmente quando crianças com atraso de crescimento apresentam simultaneamente sindactilia do segundo e terceiro dedos do pé e microcefalia e/ou narinas antevertidas entre outras anomalias).

Resumo: As doenças do ciclo da ureia são o resultado do défice enzimático de uma das enzimas que compõem a via metabólica de excreção do azoto. Com a excepção do défice na transcarbamilase da ornitina, que está ligado ao cromossoma X, todas as doenças são autossómicas recessivas. A apresentação clínica destas doenças pode ocorrer no período neonatal, durante a infância ou mesmo na adolescência ou idade adulta. A hiperamoniemia, as alterações urinárias e plasmáticas dos aminoácidos e ácidos orgânicos, constituem os principais marcadores bioquímicos das doenças do ciclo da ureia. O tratamento nutricional baseia-se na implementação de uma dieta restrita em proteína natural e suplementada com uma mistura de aminoácidos essenciais. O aporte proteico tem de ser constantemente ajustado em função do controlo metabólico, da avaliação antropométrica e da medicação usada para explorar as vias alternativas de excreção do azoto. A monitorização do estado nutricional assume uma importância crucial no seguimento destes doentes, de modo a melhor aferir as suas reais necessidades, prevenindo a insuficiência proteica, a qual poderá afectar negativamente o crescimento e desenvolvimento.

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A hiperglicinémia não cetótica é um erro inato da degradação da glicina, resultando na sua excessiva acumulação nos tecidos corporais, designadamente no sistema nervoso central. Trata-se de uma doença muito grave e uma das terapêuticas recentemente propostas consiste na associação do dextrometorfano com o benzoato de sódio em altas doses. Admite-se a possibilidade de o dextrometorfano bloquear o complexo-canal receptor de N-metil-D-aspartato, implicado na toxicidade da hiperglicinémia ao nível do cérebro e de o benzoato reduzir os níveis de glicina, pela sua conjugação e eliminação como hipurato. Relatamos dois casos clínicos de crianças com hiperglicinémia não cetótita, actualmente com mais de 15 meses de idade, as quais foram medicadas com dextrometorfano e benzoato de sódio desde as primeiras semanas após o parto. Não obstante se ter verificado sobrevivência para além do período neonatal e aquisição de autonomia respiratória, a evolução neurológica, até à data, não tem sido satisfatória, porventura devido ao atraso no início da terapêutica.