Consenso mexicano de tirosinemia tipo 1

INTRODUCTION: Tyrosinemia type 1 is a rare disease with autosomal recessive inheritance, featuring various clinical manifestations. These may encompass acute neonatal liver failure, neonatal cholestatic syndrome, chronic hepatitis, cirrhosis, hepatocellular carcinoma, and, alternatively, kidney disorders like renal tubular acidosis, Fanconi syndrome, hypophosphatemic rickets, among other alterations. Diagnosis relies on detecting toxic metabolites in the blood and urine, ideally confirmed through molecular testing. METHOD: A consensus was reached with experts in the field of inborn errors of metabolism (EIM), including eight pediatric gastroenterologists, two EIM specialists, two geneticists, three pediatric nutritionists specialized in EIM, and a pediatric surgeon specializing in transplants. Six working groups were tasked with formulating statements and justifications, and 32 statements were anonymously voted on using the Likert scale and the Delphi method. The first virtual vote achieved an 80% consensus, with the remaining 20% determined in person. RESULTS: The statements were categorized into epidemiology, clinical presentation, diagnosis, nutritional and medical treatment, and genetic counseling. CONCLUSIONS: This consensus serves as a valuable tool for primary care physicians, pediatricians, and pediatric gastroenterologists, aiding in the prompt diagnosis and treatment of this disease. Its impact on the morbidity and mortality of patients with tyrosinemia type 1 is substantial.

INTRODUCCIÓN: La tirosinemia tipo 1 es una enfermedad rara, con herencia autosómica recesiva, con múltiples manifestaciones clínicas, que pueden comprender desde falla hepática aguda neonatal, síndrome colestásico neonatal, hepatitis crónica, cirrosis o hepatocarcinoma, hasta alteraciones renales como acidosis tubular renal, síndrome de Fanconi o raquitismo hipofosfatémico, entre otras. El diagnóstico se basa en la presencia de metabolitos tóxicos en la sangre y la orina, idealmente con la confirmación molecular de la enfermedad. MÉTODO: Se realizó un consenso con expertos en el área de los errores innatos del metabolismo (EIM): ocho gastroenterólogos pediatras, dos médicos especialistas en EIM, dos genetistas, tres nutriólogas pediatras especializadas en EIM y un cirujano pediatra especialista en trasplantes. Se formaron seis mesas de trabajo encargadas de desarrollar los enunciados con sus justificaciones y fueron votados anónimamente 32 enunciados en una escala Likert con un método Delphi. La primera votación fue virtual, obteniendo consenso del 80% de los enunciados, y la segunda fue presencial, obteniendo el 20% restante. RESULTADOS: Los enunciados fueron divididos en epidemiología, cuadro clínico, diagnóstico, tratamiento nutricional y médico, y consejo genético. CONCLUSIONES: Este consenso constituye una valiosa herramienta para los médicos de atención primaria, pediatras y gastroenterólogos pediátricos, ya que ayuda a diagnosticar y tratar rápidamente esta enfermedad. Su impacto en la morbilidad y mortalidad de los pacientes con tirosinemia tipo 1 es sustancial.

Kawasaki Disease Associated with SARS-CoV2 in a Pair of Triplets.

The etiology of Kawasaki disease (KD) and its precise genetic basics remain unknown. Genetic variants affecting immunity have been found in some patients. The occurrence of KD in siblings is rare, but KD pedigrees with multiple affected members have been described in Japan and North America. Cases in twins have been documented. We report 2 pairs of trizygotic triplets who developed KD associated with SARS-CoV2 infection from 2 different families. Our cases show that KD is multifactorial in origin, and both infectious etiology (particularly SARS-CoV2 as in our cases) and genetic factors are relevant in the disease.

First Report of Mexican Patients with PACS1-Related Neurodevelopmental Disorder and Review of the PACS1-, PACS2-, and WDR37-Related Ophthalmological Manifestations.

Introduction: PACS1-related neurodevelopmental disorder (PACS1-related NDD) is caused by pathogenic variants in the PACS1 gene and is characterized by a distinctive facial appearance, intellectual disability, speech delay, seizures, feeding difficulties, cryptorchidism, hernias, and structural anomalies of the brain, heart, eye, and kidney. There is a marked facial resemblance and a common multisystem affectation with patients carrying pathogenic variants in the WDR37 and PACS2 genes, although they vary in terms of severity and eye involvement. Case Presentation: Here, we describe 4 individuals with PACS1-related NDD from Mexico, all of them carrying a de novo PACS1 variant c.607C>T; p.(Arg203Trp) identified by exome sequencing. In addition to eye colobomata, this report identified corneal leukoma, cataracts, and tortuosity of retinal vessels as ophthalmic manifestations not previously reported in patients with PACS1-related NDD. Discussion: We reviewed the ocular phenotypes reported in 74 individuals with PACS1-related NDD and the overlaps with WDR37- and PACS2-related syndromes. We found that the 3 syndromes have in common the presence of colobomata, ptosis, nystagmus, strabismus, and refractive errors, whereas microphthalmia, microcornea, and Peters anomaly are found only among individuals with PACS1-related NDD and WDR37 syndrome, being more severe in the latter. This supports the previous statement that the so-called WDR37-PACS1-PACS2 axis might have an important role in ocular development and also that the specific ocular findings could be useful in the clinical differentiation between these related syndromes.

Improved HUMARA for the Detection of X-Linked Agammaglobulinemia Carriers.

Background: Fragment analysis of exon 1 of the human androgen receptor, known as HUMARA, is a polymerase chain reaction (PCR)-based method for detecting X-linked agammaglobulinemia (XLA) carriers. This method takes advantage of X-chromosome inactivation (XCI) in female cells. XLA is caused by mutations in the Bruton tyrosine kinase (BTK) gene, located in Xq22.1. In this study, XCI is nonrandom or skewed in B-cells. B-cells with an active X-chromosome carrying a BTK mutation do not mature. Peripheral B-cells in XLA carriers inactivate the mutated X-chromosome. Methods: HUMARA was performed using DNA from purified B-cells and total leukocytes. DNA was digested using methylation-sensitive HhaI. The PCR of the HUMARA polymorphic marker was performed with the HhaI digested samples. The lengths of the PCR products were determined. If a suspected carrier showed skewed XCI in their B-cells, the marker length that corresponded with the length determined in the index patient indicated their carrier status. Results: HUMARA was conducted on purified B-cells; this allowed easier identification of the mutated or inactive allele, as the active allele was enzymatically digested. Analysis of 30 possible carriers using modified HUMARA corroborated that the carrier status in all samples that were heterozygous for the marker using XCI calculation for leukocytes showed a Gaussian distribution, while the carrier B-cell DNA showed a skewed XCI. Conclusion: Carrier status was successfully determined for most of the analyzed samples. B-cell enrichment resulted in precise carrier determination data, reduced the sample size, and facilitated inactive and active allele identification.

Analysis of the CAG tract length in the Androgen Receptor gene in Mexican patients with nonsyndromic cryptorchidism.

OBJECTIVES: Cryptorchidism is the most common genitourinary birth defect in live newborn males and is considered as an important risk factor for testicular germ cell tumors and infertility. The Androgen Receptor gene is important in this pathology due to its participation, mainly, in the inguinoscrotal phase of testicular descent. We determine the length of the CAG tract in the Androgen Receptor (AR) gene in Mexican patients with nonsyndromic cryptorchidism. METHODS: One hundred and 15 males were included; of these, 62 had nonsyndromic cryptorchidism and 53 were healthy volunteers. DNA was extracted from a peripheral blood samples, subsequently, the CAG tract in exon 1 of AR gene was amplified by PCR and sequenced. RESULTS: Mexican patients with nonsyndromic cryptorchidism presented 25.03 ± 2.58 repeats of CAG tract in the AR gene compared to 22.72 ± 3.17 repeats of CAG tract in Mexican healthy individuals (p≤0.0001; t value of 4.3). Furthermore, the deletion of codon 57 that corresponds to the deletion of a leucine residue at position 57 (Del L57) in the AR gene was found for the first time in a nonsyndromic cryptorchidism patient. This molecular alteration has been related previously to testicular germ cell tumor (TGCT). CONCLUSIONS: The CAG tract in the AR gene is longer in patients with nonsyndromic cryptorchidism than in healthy individuals, supporting the association between this polymorphism of the AR gene and nonsyndromic cryptorchidism in the Mexican population.

Cryptorchidism and Testicular Tumor: Comprehensive Analysis of Common Clinical Features and Search of SNVs in the KIT and AR Genes.

Allelic variants in genes implicated in the development of testicular germ cell tumor (TGCT) could be present in patients with cryptorchidism (CO). Currently; the mechanisms explaining this relationship are still unknown. In this study the common clinical features in patients with CO and TGCT and 6 variants of KIT and AR genes associated to TGCT were analyzed. Population analyzed included 328 individuals: 91 patients with CO; 79 with TGCT, 13 of them with previous CO diagnosis, and 158 healthy males. Of the 13 patients with TGCT and history of CO, one patient (7.7%) presented the heterozygous form of the variant rs121913507 and two patients (15.4%) presented homozygote genotype for the variant rs121913506 in KIT gene. Interestingly, the heterozygous form for the variant rs121913506 of KIT gene was identifying in all of 13 patients. The rs201934623, rs774171864, and rs12014709 variants of the AR gene did not show any clinical association. Our results strongly support that genetic component in CO could be conditioning for the development of TGCT. Notably, KIT gene variants might be determinants in the pathological association between TGCT and CO.

Epigenetic and risk factors of testicular germ cell tumors: a brief review.

Testicular germ cell cancer (TGCT) is the most common malignancy among young adult males, which has become important due to its increased incidence and mortality in the population worldwide. The etiology is multifactorial. Recent studies have shown some associations between the development of isolated TGCT and certain risk factors, such as exposure to endocrine disruptors, cryptorchidism, and family history of cancer, in order to identify the key pieces in carcinogenesis. Some of the most important findings in recent years is the association of different genes, such as c-KIT/KITLG, expression of the miR-371-373 cluster and protein expression as c-KIT and POU5F1 in the development of this neoplasia, and the identification of new molecular markers as TGFBR3 gene, identifying aberrant methylation patterns in promoter regions of several genes, expression of miR-1297 which regulates PTEN and protein expression as DMTR1. In the future, a multidisciplinary research strategy could provide valuable new insights into the etiology of TGCTs, which support clinical diagnosis of TGCT in the next years to increase survival in this kind of patients.

Angelman Syndrome due to familial translocation: unexpected additional results characterized by Microarray-based Comparative Genomic Hybridization.

BACKGROUND: The 15q11q13 region is subject to imprinting and is involved in various structural rearrangements. Less than 1% of Angelman Syndrome patients are due to translocations involving 15q11q13. These translocations can arise de novo or result from the segregation of chromosomes involved in a familial balanced translocation. RESULTS: A 5-year-old Mexican girl presented with developmental delay, minor dysmorphic features and history of exotropia. G-banding chromosome analysis established the diagnosis of Angelman Syndrome resulting from a familial translocation t(10;15) involving the 15q11.2 region. The available family members were studied using banding and molecular cytogenetic techniques, including Microarray-based Comparative Genomic Hybridization, which revealed additional unexpected results: a coincidental and smaller 15q deletion, asymptomatic duplications in 15q11.2 and Xp22.31 regions. CONCLUSIONS: This report demonstrates the usefulness of array CGH for a detailed characterization of familial translocations, including the detection of submicroscopic copy number variations, which would otherwise be missed by karyotype analysis alone. Our report also expands two molecularly characterized rare patient cohorts: Angelman Syndrome patients due to familial translocations and patients with 15q11.2 duplications of paternal origin.