Browsing by Author "Lay-Son, Guillermo"
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Item Case fatality rate and associated factors in patients with 22q11 microdeletion syndrome: a retrospective cohort study(BMJ Publishing Group, 2014) Repetto, Gabriela; Guzmán, Maria Luisa; Delgado, Iris; Loyola, Hugo; Palomares, Mirta; Lay-Son, Guillermo; Vial, Cecilia; Benavides, Felipe; Espinoza, Karena; Alvarez, PatriciaOBJECTIVE: Chromosome 22q11.2 deletion is the most commonly occurring known microdeletion syndrome. Deaths related to the syndrome have been reported, but the magnitude of death has not been quantified. This study evaluated the deletion's impact on survival and its clinical manifestations in a large cohort of Chilean patients. DESIGN: Demographic and clinical data of individuals with 22q11 deletions diagnosed between 1998 and 2013 were collected from medical records and death certificates. Case fatality rate was calculated and compared with national vital statistics. OR with 95% CI analysis was used to assess the association between clinical manifestations and death. SETTING: Genetic services in tertiary care centres in Chile, following patients with 22q11.2 deletion. OUTCOMES: Fatality rate and associated factors. RESULTS: 59 of 419 patients (14.1%) died during the study period at a median of 3.4 months (range 0 to 32 years of age). Factors associated with death included congenital heart disease (OR 5.27; 95% CI 2.06 to 13.99; p<0.0001), hypocalcaemia (OR 4.27; 95% CI 1.67 to 11.15; p<0.002) and airway malacia (OR 13.37; 95% CI 1.19 to 110.51; p<0.002). Patients with deletions and defects such as tetralogy of Fallot with or without pulmonary atraesia, truncus arteriosus or ventricular septal defect, had a 2.6-fold to 4.6-fold higher death rate compared with nationwide reports for the same types of defects. CONCLUSIONS: In this cohort, we observed a death rate of 14.1%, implying that one in seven patients with 22q11 deletion died during the study period. Significant associations with cardiac defects, hypocalcaemia and airway malacia were observed. Furthermore, the death risk in patients with 22q11 deletion and cardiac defects exceeded the global figures observed in Chile for infants with structurally similar but apparently isolated anomalies. These observations indicate a need to identify patients who may require specific perioperative management to improve survival.Item Chromosomal microarrays testing in children with developmental disabilities and congenital anomalies(Sociedad Brasileira de Pediatria with Elsevier, 2015) Lay-Son, Guillermo; Espinoza, Karena; Vial, Cecilia; Rivera, Juan; Guzmán, María; Repetto, GabrielaObjectives Clinical use of microarray-based techniques for the analysis of many developmental disorders has emerged during the last decade. Thus, chromosomal microarray has been positioned as a first-tier test. This study reports the first experience in a Chilean cohort. Methods Chilean patients with developmental disabilities and congenital anomalies were studied with a high-density microarray (CytoScan™ HD Array, Affymetrix, Inc., Santa Clara, CA, USA). Patients had previous cytogenetic studies with either a normal result or a poorly characterized anomaly. Results This study tested 40 patients selected by two or more criteria, including: major congenital anomalies, facial dysmorphism, developmental delay, and intellectual disability. Copy number variants (CNVs) were found in 72.5% of patients, while a pathogenic CNV was found in 25% of patients and a CNV of uncertain clinical significance was found in 2.5% of patients. Conclusion Chromosomal microarray analysis is a useful and powerful tool for diagnosis of developmental diseases, by allowing accurate diagnosis, improving the diagnosis rate, and discovering new etiologies. The higher cost is a limitation for widespread use in this setting.Item Cystic fibrosis in Chilean patients: Analysis of 36 common CFTR gene mutations(Elsevier, 2012) Collaborative Group of the Chilean National Cystic Fibrosis Program; Lay-Son, Guillermo; Puga, Alonso; Astudillo, Pedro; Repetto, GabrielaBACKGROUND: CFTR gene mutations have worldwide differences in prevalence and data on Chilean patients is scarce. METHODS: We studied 36 of the most common CFTR mutations in Chilean patients from the CF National Program [Programa Nacional de Fibrosis Quística (PNFQ)] of the Ministry of Health of Chile. RESULTS: Two hundred and eighty-nine patients were studied. Fourteen different mutations were identified with an overall allele detection rate of 42.0%. Mutations with frequencies greater than 1% were p.F508del (30.3% of alleles), p.R334W (3.3%), p.G542X (2.4%), c.3849+10Kb C>T (1.7%), and p.R553X (1.2%). A north to south geographical gradient was observed in the overall rate of detection. CONCLUSIONS: Southern European CFTR mutations predominate in the Chilean population, but a high percentage of alleles remain unknown. Geographical heterogeneity could be explained in part by admixture. Complementary analyses are necessary to allow for effective genetic counselling and improve cost-effectiveness of screening and diagnostic tests.Publication Decoding complex inherited phenotypes in rare disorders: the DECIPHERD initiative for rare undiagnosed diseases in Chile(2024) Poli Harlowe, María Cecilia; Rebolledo Jaramillo, Boris; Lagos, Catalina; Orellana, Joan; Moreno, Gabriela; Martín, Luz M.; Encina, Gonzalo; Böhme, Daniela; Faundes, Víctor; Zavala, M. Jesús; Hasbún, María Trinidad; Fischer, Sara; Brito, Florencia; Araya, Diego; Lira, Manuel; Cruz, Javiera de la; Astudillo, Camila; Lay-Son, Guillermo; Cares, Carolina; Aracena, Mariana; San Martín, Esteban; Coban-Akdemir, Zeynep; Posey, Jennifer E.; Lupski, James R.; Repetto, GabrielaRare diseases affect millions of people worldwide, and most have a genetic etiology. The incorporation of next-generation sequencing into clinical settings, particularly exome and genome sequencing, has resulted in an unprecedented improvement in diagnosis and discovery in the past decade. Nevertheless, these tools are unavailable in many countries, increasing health care gaps between high- and low-and-middle-income countries and prolonging the “diagnostic odyssey” for patients. To advance genomic diagnoses in a setting of limited genomic resources, we developed DECIPHERD, an undiagnosed diseases program in Chile. DECIPHERD was implemented in two phases: training and local development. The training phase relied on international collaboration with Baylor College of Medicine, and the local development was structured as a hybrid model, where clinical and bioinformatics analysis were performed in-house and sequencing outsourced abroad, due to lack of high-throughput equipment in Chile. We describe the implementation process and findings of the first 103 patients. They had heterogeneous phenotypes, including congenital anomalies, intellectual disabilities and/or immune system dysfunction. Patients underwent clinical exome or research exome sequencing, as solo cases or with parents using a trio design. We identified pathogenic, likely pathogenic or variants of unknown significance in genes related to the patients´ phenotypes in 47 (45.6%) of them. Half were de novo informative variants, and half of the identified variants have not been previously reported in public databases. DECIPHERD ended the diagnostic odyssey for many participants. This hybrid strategy may be useful for settings of similarly limited genomic resources and lead to discoveries in understudied populations.Item Exome Sequencing Identifies Genetic Variants Associated with Extreme Manifestations of the Cardiovascular Phenotype in Marfan Syndrome(2022) Jimenez, Yanireth; Paulsen, Cesar; Turner, Eduardo; Iturra, Sebastian; Cuevas, Oscar; Lay-Son, Guillermo; Repetto, Gabriela; Rojas, Marcelo; Calderon, JuanMarfan Syndrome (MFS) is an autosomal dominant condition caused by variants in the fibrillin-1 (FBN1) gene. Cardinal features of MFS include ectopia lentis (EL), musculoskeletal features and aortic root aneurysm and dissection. Although dissection of the ascending aorta is the main cause of mortality in MFS, the clinical course differs considerably in age of onset and severity, even among individuals who share the same causative variant, suggesting the existence of additional genetic variants that modify the severity of the cardiovascular phenotype in MFS. We recruited MFS patients and classified them into severe (n = 8) or mild aortic phenotype (n = 14) according to age of presentation of the first aorta-related incident. We used Exome Sequencing to identify the genetic variants associated with the severity of aortic manifestations and we performed linkage analysis where suitable. We found five genes associated with severe aortic phenotype and three genes that could be protective for this phenotype in MFS. These genes regulate components of the extracellular matrix, TGFβ pathway and other signaling pathways that are involved in the maintenance of the ECM or angiogenesis. Further studies will be required to understand the functional effect of these variants and explore novel, personalized risk management and, potentially, therapies for these patients.Publication Genetic Testing to Inform Epilepsy Treatment Management From an International Study of Clinical Practice(2022) McKnight, Dianalee; Morales, Ana; Hatchell, Kathryn E.; Bristow, Sara L.; Bonkowsky, Joshua L.; Scott Perry, Michael; Berg, Anne T.; Borlot, Felippe; Esplin, Edward D.; Moretz, Chad; Angione, Katie; Ríos-Pohl, Loreto; Nussbaum, Robert L.; Aradhya, Swaroop; ELEVIATE Consortium; Haldeman-Englert, Chad R.; Levy, Rebecca J.; Parachuri, Venu G.; Lay-Son, Guillermo; Dávila-Ortiz de Montellano, David J.; Ramírez-García, Miguel Angel; Benítez Alonso, Edmar O.; Ziobro,Julie; Chirita-Emandi, Adela; Felix, Temis M.; Kulasa-Luke, Dianne; Megarbane, Andre; Karkare, Shefali; Chagnon, Sarah L.; Humberson, Jennifer B.; Assaf, Melissa J.; Silva, Sebastián; Zarroli, Katherine; Boyarchuk, Oksana; Nelson, Gary R.; Palmquist, Rachel; Katherine C Hammond; Hwang, Sean T.; Boutlier, Susan B.; Nolan Melinda; Batley, Kaitlin Y.; Chavda, Devraj; Reyes-Silva, Carlos Alberto; Miroshnikov, Oleksandr; Zuccarelli, Britton; Amlie-Wolf, Louis; Wheless, James W.; Seinfeld, Syndi; Venegas, VivianaImportance: It is currently unknown how often and in which ways a genetic diagnosis given to a patient with epilepsy is associated with clinical management and outcomes. Objective: To evaluate how genetic diagnoses in patients with epilepsy are associated with clinical management and outcomes. Design, setting, and participants: This was a retrospective cross-sectional study of patients referred for multigene panel testing between March 18, 2016, and August 3, 2020, with outcomes reported between May and November 2020. The study setting included a commercial genetic testing laboratory and multicenter clinical practices. Patients with epilepsy, regardless of sociodemographic features, who received a pathogenic/likely pathogenic (P/LP) variant were included in the study. Case report forms were completed by all health care professionals. Exposures: Genetic test results. Main outcomes and measures: Clinical management changes after a genetic diagnosis (ie, 1 P/LP variant in autosomal dominant and X-linked diseases; 2 P/LP variants in autosomal recessive diseases) and subsequent patient outcomes as reported by health care professionals on case report forms. Results: Among 418 patients, median (IQR) age at the time of testing was 4 (1-10) years, with an age range of 0 to 52 years, and 53.8% (n = 225) were female individuals. The mean (SD) time from a genetic test order to case report form completion was 595 (368) days (range, 27-1673 days). A genetic diagnosis was associated with changes in clinical management for 208 patients (49.8%) and usually (81.7% of the time) within 3 months of receiving the result. The most common clinical management changes were the addition of a new medication (78 [21.7%]), the initiation of medication (51 [14.2%]), the referral of a patient to a specialist (48 [13.4%]), vigilance for subclinical or extraneurological disease features (46 [12.8%]), and the cessation of a medication (42 [11.7%]). Among 167 patients with follow-up clinical information available (mean [SD] time, 584 [365] days), 125 (74.9%) reported positive outcomes, 108 (64.7%) reported reduction or elimination of seizures, 37 (22.2%) had decreases in the severity of other clinical signs, and 11 (6.6%) had reduced medication adverse effects. A few patients reported worsening of outcomes, including a decline in their condition (20 [12.0%]), increased seizure frequency (6 [3.6%]), and adverse medication effects (3 [1.8%]). No clinical management changes were reported for 178 patients (42.6%). Conclusions and relevance: Results of this cross-sectional study suggest that genetic testing of individuals with epilepsy may be materially associated with clinical decision-making and improved patient outcomes.Item Growth in Chilean infants with chromosome 22q11 microdeletion syndrome(John Wiley & Sons, 2012) Guzman, Maria; Delgado, Iris; Lay-Son, Guillermo; Williams, Edward; Puga, Alonso; Repetto, GabrielaChromosome 22q11 microdeletion syndrome has a wide range of clinical manifestations including congenital heart malformations, palatal defects, endocrine abnormalities, immunologic deficits, learning difficulties, and an increased predisposition to psychiatric disease. Short stature and poor weight gain in infancy are common findings and are usually seen in the absence of hormone deficiencies. An increased frequency of obesity has been observed in adolescents and adults. We generated gender-specific growth curves from 0 to 24 months of age, based on 479 length and 475 weight measurements from 138 Chilean patients with 22q11 deletion. Final adult height and weight on 25 individuals were analyzed. The 10th, 50th, and 90th centile-smoothed curves for infants were built using the LMS method and compared with World Health Organization Child Growth Standards. The 50th centile for length in the deleted patients was slightly lower than the 10th centile of WHO standards in boys and girls. The same was observed for weight, although a trend toward a gradual increase near 2 years of age was observed, particularly in boys. Average adult height was 152 cm (ranging from 143 to 162 cm) in females, corresponding to the 10th centiles of WHO standards, and 166 cm for males (160-172 cm), at the 20th centile of WHO standards. A third of the adult females and none of the males had body mass index (BMI) greater than 25. The curves should be useful to monitor growth in infants with 22q11 microdeletion syndrome.Item Medical genetics and genetic counseling in Chile(Springer, 2013) Margarit, Sonia; Alvarado, Monica; Alvarez, Karin; Lay-Son, GuillermoIn the South American Republic of Chile genetic counseling is not currently recognized as an independent clinical discipline, and in general is provided by physicians with training in clinical genetics. At present only one genetic counselor and 28 clinical geneticists practice in this country of over 16 million inhabitants. Pediatric dysmorphology constitutes the primary area of practice in clinical genetics. Although the country has a universal health care system and an adequate level of health care, genetic conditions are not considered a health care priority and there is a lack of clinical and laboratory resources designated for clinical genetics services. Multiple educational, cultural and financial barriers exist to the growth and development of genetic counseling services in Chile. However, during the last 10 years increased awareness of the importance of identifying individuals at risk for inherited cancer syndromes led to growing interest in the practice of cancer genetics.Item Palate abnormalities in Chilean patients with chromosome 22q11 microdeletion syndrome(Elsevier, 2012) Lay-Son, Guillermo; Palomares, Mirta; Guzman, Luisa; Vasquez, Marcos; Puga, Alonso; Repetto, GabrielaOBJECTIVE: Chromosome 22q11 microdeletion syndrome (del22q11) is the most frequent microdeletion syndrome in humans, with an estimated incidence of 1/4000. It is recognized as a common identifiable cause of cleft palate. We characterized palatal abnormalities in a large cohort of Chilean patients with del22q11. METHODS: Patients with the deletion were evaluated by geneticists and speech pathologists, including nasopharyngoscopy when indicated. Comparisons between groups with and without palatal abnormalities were performed using Fisher's exact test and Mann-Whitney U test. RESULTS: Two hundred and one patients were included in the study. Palate abnormalities were present in 154 patients (76.6%). The most frequent finding was submucous cleft palate (both classic and occult forms) seen in 80 patients (39.8% of the total group). Overt cleft palate or cleft lip/palate was seen in 30 patients (14.9%). Patients without palate abnormalities had significantly greater frequency of congenital heart disease and higher mortality. CONCLUSIONS: Our data show a high frequency of palate abnormalities without significant association with congenital heart disease. The most common types of palate defects seen in this series are usually not evident on physical examination and thus require a high index of suspicion and active evaluation through nasopharyngoscopy.Item Partial microduplication in the histone acetyltransferase complex member KANSL1 is associated with congenital heart defects in 22q11.2 microdeletion syndrome patients(Nature, 2017) Leon, Luis; Benavides, Felipe; Karena, Espinoza; Vial, Cecilia; Alvarez, Patricia; Palomares, Mirta; Lay-Son, Guillermo; Miranda, Macarena; Repetto, Gabriela22q11.2 microdeletion syndrome (22q11.2DS) is the most common microdeletion disorder in humans, with an incidence of 1/4000 live births. It is caused by a heterozygous deletion of 1.5–3 Mb on chromosome region 22q11.2. Patients with the deletion present features that include neuropsychiatric problems, craniofacial abnormalities and cardiovascular malformations. However, the phenotype is highly variable and the factors related to the clinical heterogeneity are not fully understood. About 65% of patients with 22q11.2DS have congenital heart defects (CHD). The main goal of this study was to identify common CNVs in 22q11.2DS patients that could be associated with the incomplete penetrance of CHD. Analysis of genomic DNA from 253 patients with 22q11.2DS using array technology showed an association between a microduplication located in region 17q21.31 and CHD (p-value = 0.023, OR = 2.75, 95% CI = 1.17–7.03). This region includes the first three exons of KANSL1 gene. Bioinformatic analysis showed that KANSL1 and CRKL, a gene in the commonly deleted region of 22q11.2DS, are part of the same regulatory module in a miRNA-mRNA network. These results show that a KANSL1 microduplication, in combination with the 22q11.2 deletion, is associated with increased risk of CHD in these patients, suggesting that KANSL1 plays a role as a modifier gene in 22q11.2DS patients.Item Proximal Deletion of 6q Overlapping with Toriello-Carey Facial Phenotype: Prenatal Findings, Clinical Course, Differential Diagnosis, and Review(2017) Catena, Sofía; Aracena, Mariana; Pizarro, Oscar; Espinoza, Karena; Lay-Son, GuillermoProximal deletion of 6q is a relatively rare chromosomal abnormality. Reported patients have deletions of different sizes but share partial overlap and present with similar clinical features, and some of them were described prior to the introduction of chromosome microarrays. We describe a male patient with prenatal sonographic findings of nuchal edema, intrauterine growth restriction, renal pelvis dilatation, and oligohydramnios. At birth, facial dysmorphism, retro/micrognathia, a short and wide neck as well as cardiovascular and renal anomalies were noted. His clinical evolution has been marked by failure to thrive, severe developmental delay, and cognitive impairment. The diagnosis of Toriello-Carey syndrome (TCS) was based on his “gestalt.” aCGH identified a de novo proximal deletion of 17 Mb in 6q (6q12q14.3). Deletion 6q13q14 seems to be responsible for the main facial features and should be considered within the differential diagnosis of TCS.Item Severe SOPH syndrome due to a novel NBAS mutation in a 27-year-old woman-Review of this pleiotropic, autosomal recessive disorder: Mystery solved after two decades(2020) Lacassie, Yves; Johnson, Britt; Lay-Son, Guillermo; Quintana, Rita; King, Andrew; Cortes, Fanny; Alvarez, Cecilia; Gomez, Ricardo; Vargas, Alfonso; Chalew, Stuart; King, Alejandra; Guardia, Sylvia; Sorensen, Ricardo U; Aradhya, SwaroopAutosomal recessive SOPH syndrome was first described in the Yakuts population of Asia by Maksimova et al. in 2010. It arises from biallelic pathogenic variants in the NBAS gene and is characterized by severe postnatal growth retardation, senile facial appearance, small hands and feet, optic atrophy with loss of visual acuity and color vision, and normal intelligence (OMIM #614800). The presence of Pelger-Hüet anomaly in this disorder led to its name as an acronym for Short stature, Optic nerve atrophy, and Pelger-Hüet anomaly. Recent publications have further contributed to the characterization of this syndrome through additional phenotype-genotype correlations. We review the clinical features described in these publications and report on a 27-year-old woman with dwarfism with osteolysis and multiple skeletal problems, minor anomalies, immunodeficiency, diabetes mellitus, and multiple secondary medical problems. Her condition was considered an unknown autosomal recessive disorder for many years until exome sequencing provided the diagnosis by revealing a founder disease-causing variant that was compound heterozygous with a novel pathogenic variant in NBAS. Based on the major clinical features of this individual and others reported earlier, a revision of the acronym is warranted to facilitate clinical recognition.