Influence of blood phenylalanine level variations on the development of executive functions and social cognition in children with phenylketonuria.

OBJECTIVE: To investigate the performance of 27 children with phenylketonuria (PKU) in tests of Executive Functions (EF) and Social Cognition (SC), and their associations with metabolic control inferred by phenylalanine (Phe) levels. METHODS: The PKU group was dichotomized according to baseline Phe-levels into; "classical PKU"(n = 14), with Phe-levels above 1200 µmol/L (> 20 mg/dL); and "mild PKU" (n = 13) with Phe-between 360 and 1200 µmol/L (6-20 mg/dL). The neuropsychological assessment focused on the EF and SC subtests of the NEPSY-II battery and intellectual performance. Children were compared to age-matched healthy participants. RESULTS: Participants with PKU presented significantly lower Intellectual Quotient (IQ) compared to controls (p = 0.001). Regarding EF analysis adjusted by age and IQ, significant differences between groups were observed only in the executive attention subtests (p = 0.029). The SC set of variables was significantly different between groups (p = 0.003), as in the affective recognition task (p < 0.001). In the PKU group, the relative variation of Phe-achieved 32.1 ± 21.0%. Relative Phe-variation was correlated only with measures of Working Memory (p < 0.001), Verbal Fluency (p = 0.004), Inhibitory Control (p = 0.035) and Theory of Mind (p = 0.003). CONCLUSIONS: Phonological Verbal Fluency, Working Memory, Inhibitory Control, and Theory of Mind were shown to be most vulnerable when there is non-ideal metabolic control. Variations in the level of Phe-may have a selective negative effect on Executive Functions and Social Cognition, but not on intellectual performance.

Influence of blood phenylalanine level variations on the development of executive functions and social cognition in children with phenylketonuria

Abstract Objective: To investigate the performance of 27 children with phenylketonuria (PKU) in tests of Executive Functions (EF) and Social Cognition (SC), and their associations with metabolic control inferred by phenylalanine (Phe) levels. Methods: The PKU group was dichotomized according to baseline Phe-levels into; "classical PKU"(n = 14), with Phe-levels above 1200 µmol/L (> 20 mg/dL); and "mild PKU" (n = 13) with Phe-between 360 and 1200 µmol/L (6-20 mg/dL). The neuropsychological assessment focused on the EF and SC subtests of the NEPSY-II battery and intellectual performance. Children were compared to age-matched healthy participants. Results: Participants with PKU presented significantly lower Intellectual Quotient (IQ) compared to controls (p = 0.001). Regarding EF analysis adjusted by age and IQ, significant differences between groups were observed only in the executive attention subtests (p = 0.029). The SC set of variables was significantly different between groups (p = 0.003), as in the affective recognition task (p < 0.001). In the PKU group, the relative variation of Phe-achieved 32.1 ± 21.0%. Relative Phe-variation was correlated only with measures of Working Memory (p < 0.001), Verbal Fluency (p = 0.004), Inhibitory Control (p = 0.035) and Theory of Mind (p = 0.003). Conclusions: Phonological Verbal Fluency, Working Memory, Inhibitory Control, and Theory of Mind were shown to be most vulnerable when there is non-ideal metabolic control. Variations in the level of Phe-may have a selective negative effect on Executive Functions and Social Cognition, but not on intellectual performance.

CEDNIK syndrome in a Brazilian patient with compound heterozygous pathogenic variants.

CEDNIK (Cerebral Dysgenesis, Neuropathy, Ichthyosis, and Keratoderma) syndrome is a neuro ichthyotic syndrome characterized by a clinical constellation of features including severe developmental delay, microcephaly, and facial dysmorphism. Here, we report the clinical and molecular characterization of a patient with CEDNIK syndrome harboring two compound heterozygous variants in the SNAP29 gene. The patient presents a combination of a loss-of-function SNAP29 mutation and a ∼370 kb 22q11.2 deletion, each of these genetic variants inherited from one of the parents. This report provides detailed data of a patient with unprecedented genetic events leading to the CEDNIK phenotype and may contribute to the elucidation of this rare condition.

Cytogenomic assessment of the diagnosis of 93 patients with developmental delay and multiple congenital abnormalities: The Brazilian experience.

OBJECTIVE: The human genome contains several types of variations, such as copy number variations, that can generate specific clinical abnormalities. Different techniques are used to detect these changes, and obtaining an unequivocal diagnosis is important to understand the physiopathology of the diseases. The objective of this study was to assess the diagnostic capacity of multiplex ligation-dependent probe amplification and array techniques for etiologic diagnosis of syndromic patients. METHODS: We analyzed 93 patients with developmental delay and multiple congenital abnormalities using multiplex ligation-dependent probe amplifications and arrays. RESULTS: Multiplex ligation-dependent probe amplification using different kits revealed several changes in approximately 33.3% of patients. The use of arrays with different platforms showed an approximately 53.75% detection rate for at least one pathogenic change and a 46.25% detection rate for patients with benign changes. A concomitant assessment of the two techniques showed an approximately 97.8% rate of concordance, although the results were not the same in all cases. In contrast with the array results, the MLPA technique detected ∼70.6% of pathogenic changes. CONCLUSION: The obtained results corroborated data reported in the literature, but the overall detection rate was higher than the rates previously reported, due in part to the criteria used to select patients. Although arrays are the most efficient tool for diagnosis, they are not always suitable as a first-line diagnostic approach because of their high cost for large-scale use in developing countries. Thus, clinical and laboratory interactions with skilled technicians are required to target patients for the most effective and beneficial molecular diagnosis.

Cytogenomic assessment of the diagnosis of 93 patients with developmental delay and multiple congenital abnormalities: The Brazilian experience

OBJECTIVE: The human genome contains several types of variations, such as copy number variations, that can generate specific clinical abnormalities. Different techniques are used to detect these changes, and obtaining an unequivocal diagnosis is important to understand the physiopathology of the diseases. The objective of this study was to assess the diagnostic capacity of multiplex ligation-dependent probe amplification and array techniques for etiologic diagnosis of syndromic patients. METHODS: We analyzed 93 patients with developmental delay and multiple congenital abnormalities using multiplex ligation-dependent probe amplifications and arrays. RESULTS: Multiplex ligation-dependent probe amplification using different kits revealed several changes in approximately 33.3% of patients. The use of arrays with different platforms showed an approximately 53.75% detection rate for at least one pathogenic change and a 46.25% detection rate for patients with benign changes. A concomitant assessment of the two techniques showed an approximately 97.8% rate of concordance, although the results were not the same in all cases. In contrast with the array results, the MLPA technique detected ∼70.6% of pathogenic changes. CONCLUSION: The obtained results corroborated data reported in the literature, but the overall detection rate was higher than the rates previously reported, due in part to the criteria used to select patients. Although arrays are the most efficient tool for diagnosis, they are not always suitable as a first-line diagnostic approach because of their high cost for large-scale use in developing countries. Thus, clinical and laboratory interactions with skilled technicians are required to target patients for the most effective and beneficial molecular diagnosis.

Post-mortem cytogenomic investigations in patients with congenital malformations.

Congenital anomalies are the second highest cause of infant deaths, and, in most cases, diagnosis is a challenge. In this study, we characterize patterns of DNA copy number aberrations in different samples of post-mortem tissues from patients with congenital malformations. Twenty-eight patients undergoing autopsy were cytogenomically evaluated using several methods, specifically, Multiplex Ligation-dependent Probe Amplification (MLPA), microsatellite marker analysis with a MiniFiler kit, FISH, a cytogenomic array technique and bidirectional Sanger sequencing, which were performed on samples of different tissues (brain, heart, liver, skin and diaphragm) preserved in RNAlater, in formaldehyde or by paraffin-embedding. The results identified 13 patients with pathogenic copy number variations (CNVs). Of these, eight presented aneuploidies involving chromosomes 13, 18, 21, X and Y (two presented inter- and intra-tissue mosaicism). In addition, other abnormalities were found, including duplication of the TYMS gene (18p11.32); deletion of the CHL1 gene (3p26.3); deletion of the HIC1 gene (17p13.3); and deletion of the TOM1L2 gene (17p11.2). One patient had a pathogenic missense mutation of g.8535C>G (c.746C>G) in exon 7 of the FGFR3 gene consistent with Thanatophoric Dysplasia type I. Cytogenomic techniques were reliable for the analysis of autopsy material and allowed the identification of inter- and intra-tissue mosaicism and a better understanding of the pathogenesis of congenital malformations.

Investigação clínica e citogenética molecular em pacientes com atraso de desenvolvimento neuropsicomotor associado à malformação congênita / Clinical and molecular cytogenetics investigation in patients with psychomotor delay associated with congenital malformation

Introdução: Com a sofisticação das técnicas de análise do DNA, a medicina moderna tem à sua disposição boas possibilidades para elucidar quadros clínicos indefinidos em pacientes que possuem microrrearranjos cromossômicos complexos. O desenvolvimento da técnica de MLPA (Multiplex ligation-dependent probe amplification) aliado à tecnologia dos arrays (WGAS - whole genome array screening) possibilitou analisar de uma só vez, diferentes regiões de interesse clínico no genoma humano. Objetivo: O presente trabalho teve como objetivo estudar pacientes com atraso de desenvolvimento neuropsicomotor (ADNPM) associado à malformação congênita (MC) com cariótipo prévio normal ou inconclusivo. Material e métodos: Participaram do estudo 71 pacientes com ADNPM associado à MC que foram analisados utilizando o teste de MLPA com os kits P036 e P064, seguido de WGAS com as diferentes plataformas (Agilent, Affymetrix e Illumina). Resultados: Entre os 33 pacientes com alterações patogênicas e de significado clínico incerto (VOUS) encontramos: 12 pacientes com deleção, 5 com duplicação e 16 com duplicações e deleções (dup/del) concomitantes. Foram 29 pacientes com alterações patogênicas conclusivas, 4 pacientes com CNVs classificadas como VOUS e 15 pacientes tiveram resultado de array normal além dos outros 23 que apresentaram alterações benignas, ou por não apresentarem genes na região alterada, ou por serem genes sem fenótipos descritos, ou ainda, as alterações foram herdadas de genitores normais. Na casuística total foram encontrados 4 pacientes com regiões de perda de heterozigosidade. Conclusões: A utilização de uma estratégia combinada utilizando diferentes kits de MLPA, com capacidade para detectar as principais microalterações genômicas patogênicas conhecidas, associada à aplicação do WGAS possibilitou a detecção de alterações submicroscópicas, bem como a correlação clínica adequada para pacientes não diagnosticados pela citogenética clássica. Dessa forma,...

Introduction: The recent technological advances on DNA-based techniques have established in modern medicine good opportunities to elucidate undefined clinical cases in patients with complex chromosomal microrearrangements. The performance of MLPA (Multiplex ligation-dependent probe amplification) technique together with array technologies (WGAS - whole genome array screening) created the possibility of one single experiment to analyze different regions of interest in the human genome. Objective: Patients with psychomotor delay (PSMD) associated with multiple congenital anomalies who had normal or inconclusive G-band-karyotype (MCA) were studied in order to understand the genotype-phenotype correlations. Material and methods: This study involved 71 patients with psychomotor delay (PSMD) associated with multiple congenital anomalies (MCA) analyzed by MLPA (P036 and P064 kits), followed by WGAS different platforms (Agilent, Affymetrix e Illumina®). Results: Among 33 patients with pathogenic and uncertain (VOUS) copy number variations (CNV) were found: 12 deletions, 5 duplications and 16 concomitant duplication and deletion (dup/del). There were 29 patients with conclusive pathogenic findings, 4 patients with VOUS and 16 patients with normal array, but others 23 patients with benign results, which means there is no gene content in the region involved, or because these genes were not linked to phenotype, or even due to CNVs inherited of healthy parents. From the whole casuistic, 4 individuals presented loss of heterozygosity (LOH) regions. Conclusions: The use of a combined strategy of analysis (MLPA - WGAS) with a high capacity to detect pathogenic CNVs allows unraveling microscopic imbalances, and consequently, offers an adequate clinical correlation for patients not previously diagnosed by classical cytogenetics. In conclusion, this study suggests a new model for the combined application of these techniques, which represents an optimal alternative for a genomic...

Complex structural rearrangement features suggesting chromoanagenesis mechanism in a case of 1p36 deletion syndrome.

Genome rearrangements are caused by the erroneous repair of DNA double-strand breaks, leading to several alterations that result in loss or gain of the structural genomic of a dosage-sensitive genes. However, the mechanisms that promote the complexity of rearrangements of congenital or developmental defects in human disease are unclear. The investigation of complex genomic abnormalities could help to elucidate the mechanisms and causes for the formation and facilitate the understanding of congenital or developmental defects in human disease. We here report one case of a patient with atypical clinical features of the 1p36 syndrome and the use of cytogenomic techniques to characterize the genomic alterations. Analysis by multiplex ligation-dependent probe amplification and array revealed a complex rearrangement in the 1p36.3 region with deletions and duplication interspaced by normal sequences. We also suggest that chromoanagenesis could be a possible mechanism involved in the repair and stabilization of this rearrangement.

Cytogenomic characterization of an unexpected 17.6 Mb 9p deletion associated to a 14.8 Mb 20p duplication in a dysmorphic patient with multiple congenital anomalies presenting a normal G-banding karyotype.

We describe a female patient with developmental delay, dysmorphic features and multiple congenital anomalies who presented a normal G-banded karyotype at the 550-band resolution. Array and multiplex-ligation probe amplification (MLPA) techniques identified an unexpected large unbalanced genomic aberration: a 17.6Mb deletion of 9p associated to a 14.8 Mb duplication of 20p. The deleted 9p genes, especially CER1 and FREM1, seem to be more relevant to the phenotype than the duplicated 20p genes. This study also shows the relevance of using molecular techniques to make an accurate diagnosis in patients with dysmorphic features and multiple anomalies suggestive of chromosome aberration, even if on G-banding their karyotype appears to be normal. Fluorescence in situ hybridization (FISH) was necessary to identify a masked balanced translocation in the patient's mother, indicating the importance of associating cytogenetic and molecular techniques in clinical genetics, given the implications for patient management and genetic counseling.