MLPA followed by target-NGS to detect mutations in the dystrophin gene of Peruvian patients suspected of DMD/DMB.

BACKGROUND: We report the molecular analysis of the DMD gene in a group of Peruvian patients with Duchenne/Becker dystrophinopathy. This is the first study to thoroughly characterize mutations in this population. METHODS: We used the combination of multiplex ligation-dependent probe amplification (MLPA) and sequencing analysis of the DMD gene. We recruited Peruvian patients in 2 years from reference national hospitals. We performed DNA tests in 152 patients, checking first exon deletion/duplication by MLPA, and subsequently, if negative, samples were sequenced to detect point mutations. RESULTS: The average age for diagnosis was 9.8 years, suggesting a delay for timely diagnosis and care. We found causal DMD mutations in 125 patients: 72 (57.6%) exon deletions/duplications (41.6% deletions, 16.0% duplications), and 53 (42.4%) point mutations (27.2% nonsense, 9.6% small indels, and 5.6% splice site). CONCLUSION: Due to our genetic background, we expected a higher number of novel and recurrent causal mutations in our sample. Results showed 16% of novel mutations, similar to other well-studied populations.

Novel mutation in ENG gene causing Hereditary Hemorrhagic Telangiectasia in a Peruvian family.

Hereditary Hemorrhagic Telangiectasia (HHT) is a rare disorder of vascular development. Common manifestations include epistaxis, telangiectasias and arteriovenous malformations (AVMs) in multiple organs. Most patients have deletions or missense mutations in the ENG or ACVRL1 gene respectively, significantly affecting endothelium homeostasis. We analyzed the ENG gene in five members of a Peruvian family affected by HHT. One novel mutation was found in exon four of the ENG gene c.408delA, at aminoacid residue 136. This mutation changes the subsequent reading frame producing an early stop at residue 162, preserving only one fourth of the normal protein of 658 aa. This mutation was found in the four affected members of family.

A snapshot of current genetic testing practice in Lynch syndrome: The results of a representative survey of 33 Latin American existing centres/registries.

We aimed to assess the current genetics practice to manage patients with Lynch syndrome (LS) across Latin America. A Latin American LS survey was sent out to 52 centres/registries, comprising a total of 12 countries from the region. Overall, 33 centres completed the survey, of which the oldest LS registry was established in 1992 in Sao Paulo (Brazil), and the youngest this year in San Jose (Costa Rica). In total, 87% (26/30) of the participating centres/registries belonging to the nine countries are performing genetic testing. Overall, 1352 suspected families were sequenced. Pathogenic variants were identified in 34% of the families, with slightly differing distribution of variants between females and males. Path_MLH1 variants were identified in 39% of females and 50% of males (p = 0.023), while path_MSH2 were identified in 37% of females and males, followed by path_PMS2 in 11% of females and 8% of males, path_MSH6 in 13% of females and 3% of males (p < 0.001) and path_EPCAM in 0.3% of females and 2% of males. In Latin America, 9 of 12 (75%) participating countries had implemented healthcare for LS. LS screening is inconsistently applied within Latin America healthcare systems because of structural differences in the healthcare systems between the countries.

[Frequency of the most common mutations of the CFTR gene in peruvian patients with cystic fibrosis using the ARMS-PCR technique]. / Frecuencia de las mutaciones más comunes del gen CFTR en pacientes peruanos con fibrosis quística mediante la técnica ARMS-PCR.

OBJECTIVES.: To determine the frequency of the ten most common mutations of the CFTR gene reported in Latin Americausing amplification-refractory mutation system-polymerase chain reaction (ARMS-PCR) in patients with cystic fibrosis (CF) in two referral hospitals in Peru during the year 2014. MATERIALS AND METHODS.: The frequency of the ten most common mutations of the CFTR gene was assessed in patients of the Hospital Nacional Edgardo Rebagliati Martins and the Instituto Nacional de Salud del Niño, both located in Lima, Peru. Blood samples were collected from 36 patients with CF, and the ARMS-PCR technique was used to determine the presence of these mutations. RESULTS.: The study group included 73.5% of patients with a known diagnosis of CF in the country when the study was carried out. ARMS-PCR allowed three of the mutations to be identified in a combined 30.6% of the alleles from patients with CF, and 64.9% of the mutated alleles were not identified. The mutations found were p.Phe508del (22,2%), p.Gly542* (6,9%), and p.Arg1162* (1,4%). CONCLUSIONS.: There is significant variability in both the frequency and type of mutations present in our study population and in what has been reported in other Latin American countries. It is necessary to perform studies that use complete sequencing technology for the CFTR gene to identify other mutations present in our population.

Frecuencia de las mutaciones más comunes del gen CFTR en pacientes peruanos con fibrosis quística mediante la técnica ARMS-PCR / Frequency of the most common mutations of the CFTR gene in peruvian patients with cystic fibrosis using the ARMS-PCR technique

RESUMEN Objetivos. Determinar la frecuencia de las diez mutaciones más comúnmente reportadas en América Latina del gen CFTR mediante Sistema de Mutación Refractario a la amplificación por PCR (ARMS-PCR) en los pacientes con fibrosis quística (FQ) de dos instituciones hospitalarias de referencia en el Perú durante el año 2014. Materiales y métodos. Se evaluó la frecuencia de las diez comúnmente reportadas más comúnmente reportadas del gen CFTR en los pacientes del Hospital Nacional Edgardo Rebagliati Martins y el Instituto Nacional de Salud del Niño, ambos ubicados en Lima, Perú. Se recogieron muestras de sangre de 36 pacientes con FQ y se utilizó la técnica de ARMS-PCR para determinar la presencia de tales mutaciones. Resultados. Se incluyó al 73,5% de los pacientes con diagnóstico conocido de FQ en el país al momento en que se realizó el estudio. El diagnóstico por ARMS-PCR permitió identificar las mutaciones en 30,6% de los alelos de los pacientes con FQ, el 64,9% de los alelos mutados no fue identificado. Las mutaciones encontradas fueron p.Phe508del (22,2%), p.Gly542* (6,9%) y p.Arg1162* (1,4%). Conclusiones. Existe una variabilidad significativa de las mutaciones presentes en nuestra población de estudio en comparación con lo reportado en otros países de Latinoamérica, tanto en la frecuencia como en el tipo. Es necesario realizar estudios que usen la tecnología de secuenciación completa del gen CFTR para identificar otras mutaciones presentes en nuestra población.

ABSTRACT Objectives. To determine the frequency of the ten most common mutations of the CFTR gene reported in Latin Americausing amplification-refractory mutation system-polymerase chain reaction (ARMS-PCR) in patients with cystic fibrosis (CF) in two referral hospitals in Peru during the year 2014. Materials and Methods. The frequency of the ten most common mutations of the CFTR gene was assessed in patients of the Hospital Nacional Edgardo Rebagliati Martins and the Instituto Nacional de Salud del Niño, both located in Lima, Peru. Blood samples were collected from 36 patients with CF, and the ARMS-PCR technique was used to determine the presence of these mutations. Results. The study group included 73.5% of patients with a known diagnosis of CF in the country when the study was carried out. ARMS-PCR allowed three of the mutations to be identified in a combined 30.6% of the alleles from patients with CF, and 64.9% of the mutated alleles were not identified. The mutations found were p.Phe508del (22,2%), p.Gly542* (6,9%), and p.Arg1162* (1,4%). Conclusions. There is significant variability in both the frequency and type of mutations present in our study population and in what has been reported in other Latin American countries. It is necessary to perform studies that use complete sequencing technology for the CFTR gene to identify other mutations present in our population.

Genotypic and bioinformatic evaluation of the alpha-l-iduronidase gene and protein in patients with mucopolysaccharidosis type I from Colombia, Ecuador and Peru.

Mucopolysaccharidosis type I (MPSI) is a rare autosomal recessive disorder caused by mutations in the gene encoding the lysosomal enzyme α-l-iduronidase (IDUA), which is instrumental in the hydrolysis of the glycosaminoglycans, dermatan and heparan sulfate. The accumulation of unhydrolyzed glycosaminoglycans leads to pathogenesis in multiple tissue types, especially those of skeletal, nervous, respiratory, cardiovascular, and gastrointestinal origin. Although molecular diagnostic tools for MPSI have been available since the identification and characterization of the IDUA gene in 1992, Colombia, Ecuador, and Peru have lacked such methodologies. Therefore, the mutational profile of the IDUA gene in these countries has largely been unknown. The goal of this study was to characterize genotypes in 14 patients with MPSI from Colombia, Ecuador, and Peru. The most common mutation found at a frequency of 42.8% was W402X. Six patients presented with seven novel mutations, a high novel mutational rate in this population (32%). These novel mutations were validated using bioinformatic techniques. A model of the IDUA protein resulting from three of the novel missense mutations (Y625C, P385L, R621L) revealed that these mutations alter accessible surface area values, thereby reducing the accessibility of the enzyme to its substrates. This is the first characterization of the mutational profile of the IDUA gene in patients with MPSI in Colombia, Ecuador, and Peru. The findings contribute to our understanding of IDUA gene expression and IDUA enzyme function, and may help facilitate early and improved diagnosis and management for patients with MPSI.

[Mucopolysaccharidosis I, Hurler syndrome: a case report]. / Mucopolisacaridosis de tipo I Hurler: informe de un caso.

Mucopolysaccharidosis I (MPS I) is a rare, recessively inherited, lysosomal storage disorder caused by deficiency on the enzyme a-L-iduronidase. This defect results in accumulation of heparan and dermatan sulfate in different tissues and organs due to a deficiency in the catabolism of glycosaminoglycans. The overall incidence of MPS I is 0.99-1.99/100.000 live births. There are three clinical presentations: Hurler (severe), Hurler Scheie (mild) and Scheie (mild). We report the case of a 10-years-old male patient diagnosed with Hurler syndrome, the severe presentation, 5 years ago by enzyme a-L-iduronidase activity measurement in leukocytes; with a history of recurrent respiratory infections, umbilical hernia, corneal opacity, coarse facial features, macroglossia, hearing loss, stiffness of joints, cardiac compromise, claw hands, mental retardation and stunted growth. After enzyme replacement therapy the patient has shown improvement of visceral symptoms, but the neurological damage continuous in progress.

Mucopolisacaridosis de tipo I Hurler: Informe de un caso / Mucopolysaccharidosis I, Hurler syndrome: A case report

La mucopolisacaridosis de tipo I (MPS I), es una enfermedad genética autosómica recesiva de origen lisosomal, caracterizada por la deficiencia de la enzima a-L-iduronidasa. La deficiencia en el catabolismo de los glucosaminoglucanos resulta en su acumulación en diferentes tejidos y órganos. La incidencia global de la MPS I es de 0,99-1,99/100 000 nacidos vivos. Existen tres presentaciones clínicas: Hurler (grave), Hurler-Scheie (moderada) y Scheie (leve). Presentamos el caso de un niño de 10 años de edad a quien se le diagnosticó MPS I, de variedad grave en el año 2006, mediante medición de la actividad enzimática de a-L-iduronidasa en leucocitos. Este caso es el único con diagnóstico confirmado y tratamiento enzimático hasta el momento, en el Perú. Presenta infecciones respiratorias recurrentes, hernia umbilical, opacidad corneal, rasgos toscos, macroglosia, hipoacusia, rigidez articular, estenosis de la válvula pulmonar leve-moderada, manos en garra, retardo mental y retraso del crecimiento. Recibe terapia de reemplazo enzimático desde el año 2008, mostrando mejoría de los síntomas viscerales, más no del daño neurológico.

Mucopolysaccharidosis I (MPS I) is a rare, recessively inherited, lysosomal storage disorder caused by deficiency on the enzyme a-L-iduronidase. This defect results in accumulation of heparan and dermatan sulfate in different tissues and organs due to a deficiency in the catabolism of glycosaminoglycans. The overall incidence of MPS I is 0.99-1.99/100.000 live births. There are three clinical presentations: Hurler (severe), Hurler Scheie (mild) and Scheie (mild). We report the case of a 10-years-old male patient diagnosed with Hurler syndrome, the severe presentation, 5 years ago by enzyme a-L-iduronidase activity measurement in leukocytes; with a history of recurrent respiratory infections, umbilical hernia, corneal opacity, coarse facial features, macroglossia, hearing loss, stiffness of joints, cardiac compromise, claw hands, mental retardation and stunted growth. After enzyme replacement therapy the patient has shown improvement of visceral symptoms, but the neurological damage continuous in progress.

Síndrome de Proteus: presentación de dos casos / Proteus syndrome: presentation of two cases

El síndrome de Proteus es un complejo y raro desorden caracterizado por malformaciones y sobre crecimiento asimétrico de diferentes partes del cuerpo por la presencia de múltiples tejidos a modo de mosaico: nevus de tejido conectivo, nevus epidérmicos, hamartomas, lipomas, malformaciones vasculares, linfáticas y desregulación del tejido adiposo, de gran variabilidad clínica. Ponemos a consideración dos casos de síndrome de Proteus que acudieron a la consulta de Genética: la primera paciente derivada de Neurocirugía por dismorfia cráneo facial y el segundo paciente fue referido de un centro asistencial periférico por el médico pediatra, con la sospecha diagnóstica de este síndrome. En los últimos años, se ha hecho énfasis en la delimitación rigurosa de los criterios diagnósticos de esta patología, debido a los errores frecuentes de interpretación de los mismos (AU)

Proteus syndrome (PS) is a complex disorder comprising malformations and overgrowth of multiple tissues. The disorder is highly variable and appears to affect patients in a mosaic pattern: epidermal nevi, connective tissue nevi, hamartomas, lipomas, vascular and lymphatic malformations and dysregulated adipose tissue.We present two cases of PS, one of them, was refered from pediatric neurosurgeon due to cranial and face dysmorphia, the second one was refered with PS diagnosis from his pediatrician.During the last years,medical community has remarked that is necessary to make a very careful interpretation of the diagnostic criteria of this pathology, because them were misunderstood and is possible the overdiagnosis of this pathology (AU)