Action against birth defects: if not now, when?

BACKGROUND: More children are surviving through interventions to address the infectious causes of under-5 mortality; subsequently, the proportion of deaths caused by birth defects is increasing. Prevention, diagnosis, treatment and care interventions for birth defects are available but are needed where the burden is highest, low-and-middle-income countries. OBJECTIVES: A selection of birth defect focused publications, conferences, and World Health Assembly resolutions from 2000 to 2017 show that global efforts were made to raise the profile of birth defects in global public health. However, recent donor support and national government interest has waned. Without concerted global action to improve primary prevention and care for children born with birth defects, the Sustainable Development Goal targets for child survival will not be met. RESULTS: Birth defects make up 8% and 10% of global under-5 and neonatal deaths respectively, making them significant contributors to preventable loss of life for children. Survivors face long-term morbidity and lifelong disability which compounds the health and economic woes of individuals, families, communities and society as a whole. Demographic changes in sub-Saharan Africa portend a growing number of births with 1.6 billion projected from 2021 to 2050. More births and better survival without effective prevention and treatment for birth defects translates into more mortality and disability from birth defects. CONCLUSIONS: We recommend interventions for prevention of birth defects. These are evidenced-based and affordable, but require low- and middle-income countries to strengthened their health systems. Action against birth defects now will prevent premature deaths and long-term disability, and lead to stronger, more resilient health systems.

Silver-Russell syndrome-like features in a child with recombinant chromosome 11 derived from maternal pericentric inversion.

Silver-Russell syndrome (SRS) is a well-known syndrome but with heterogeneous etiologies. We present the case of a child with severe SRS-like features resulting from a complex rearrangement of chromosome 11 inherited from his mother. We studied the index case with karyotyping, MS-MLPA and molecular karyotyping. The mother was studied with karyotyping and subtelomeric FISH. We found a child with marked developmental delay and fatal outcome due to failure to thrive, carrying an 11p15 duplication and an 11q25 deletion of maternal origin. We discovered that the mother was a carrier of a pericentric inversion of chromosome 11, with a history of recurrence in other family members who had severe growth retardation and early death. To our knowledge, no similar SRS-like cases have been described in the literature. This report supports the importance of identification the causative genetic mechanism in SRS-like individuals with duplication in 11p15 region due to high risk of recurrence and to provide an appropriate genetic counseling to the family.

Decoding complex inherited phenotypes in rare disorders: the DECIPHERD initiative for rare undiagnosed diseases in Chile.

Rare 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.

Axenfeld-Rieger syndrome: more than meets the eye.

BACKGROUND: Axenfeld-Rieger syndrome (ARS) is characterised by typical anterior segment anomalies, with or without systemic features. The discovery of causative genes identified ARS subtypes with distinct phenotypes, but our understanding is incomplete, complicated by the rarity of the condition. METHODS: Genetic and phenotypic characterisation of the largest reported ARS cohort through comprehensive genetic and clinical data analyses. RESULTS: 128 individuals with causative variants in PITX2 or FOXC1, including 81 new cases, were investigated. Ocular anomalies showed significant overlap but with broader variability and earlier onset of glaucoma for FOXC1-related ARS. Systemic anomalies were seen in all individuals with PITX2-related ARS and the majority of those with FOXC1-related ARS. PITX2-related ARS demonstrated typical umbilical anomalies and dental microdontia/hypodontia/oligodontia, along with a novel high rate of Meckel diverticulum. FOXC1-related ARS exhibited characteristic hearing loss and congenital heart defects as well as previously unrecognised phenotypes of dental enamel hypoplasia and/or crowding, a range of skeletal and joint anomalies, hypotonia/early delay and feeding disorders with structural oesophageal anomalies in some. Brain imaging revealed highly penetrant white matter hyperintensities, colpocephaly/ventriculomegaly and frequent arachnoid cysts. The expanded phenotype of FOXC1-related ARS identified here was found to fully overlap features of De Hauwere syndrome. The results were used to generate gene-specific management plans for the two types of ARS. CONCLUSION: Since clinical features of ARS vary significantly based on the affected gene, it is critical that families are provided with a gene-specific diagnosis, PITX2-related ARS or FOXC1-related ARS. De Hauwere syndrome is proposed to be a FOXC1opathy.

Genetic Testing to Inform Epilepsy Treatment Management From an International Study of Clinical Practice.

Importance: 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.

Exome Sequencing Identifies Genetic Variants Associated with Extreme Manifestations of the Cardiovascular Phenotype in Marfan Syndrome.

Marfan 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, TGFß 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.

Tenorio syndrome: Description of 14 novel cases and review of the clinical and molecular features.

Tenorio syndrome (TNORS) (OMIM #616260) is a relatively recent disorder with very few cases described so far. Clinical features included macrocephaly, intellectual disability, hypotonia, enlarged ventricles and autoimmune diseases. Molecular underlying mechanism demonstrated missense variants and a large deletion encompassing RNF125, a gene that encodes for an U3 ubiquitin ligase protein. Since the initial description of the disorder in six patients from four families, several new patients were diagnosed, adding more evidence to the clinical spectrum. In this article, we described 14 additional cases with deep phenotyping and make an overall review of all the cases with pathogenic variants in RNF125. Not all patients presented with overgrowth, but instead, most patients showed a common pattern of neurodevelopmental disease, macrocephaly and/or large forehead. Segregation analysis showed that, though the variant was inherited in some patients from an apparently asymptomatic parent, deep phenotyping suggested a mild form of the disease in some of them. The mechanism underlying the development of this disease is not well understood yet and the report of further cases will help to a better understanding and clinical characterization of the syndrome.

[Consensus of the Genetics Branch of the Chilean Society of Pediatrics on the prioritization of people with Down syndrome and rare diseases for vaccination against SARS-CoV-2]. / Consenso de la Rama de Genética de la Sociedad Chilena de Pediatría sobre priorización de personas con Síndrome de Down y otras condiciones poco frecuentes en la Campaña de Vacunación COVID-19.

In the framework of the vaccination campaign against the SARS-CoV-2 virus, the Chilean Ministry of Health requested advice from the Genetics Branch of the Chilean Society of Pediatrics, to define the level of prioritization for people with Down Syndrome . A panel of geneticists worked on the development of this consensus, in which not only patients with Down syndrome were included, but the search was extended to patients with other types of disabilities, in both pediatric and adult ages in or der to contribute to the development of public health measures against the COVID-19 pandemic. The consensus concludes that, given the prevalence of comorbidities associated with Down syndrome, the higher incidence of cases with severe COVID-19 in this population group and a higher mortality, individuals with trisomy 21 should be considered as a high-risk population, and therefore, vaccina tion against SARS-CoV-2 should have a high priority for all people with Down syndrome regardless of their age (except for the age limit established by the clinical trials of each vaccine), and should be preceded only by the groups of health personnel and adults aged > 60-65 years. Likewise, this group of experts urges health authorities to include people with intellectual disabilities and related conditions as a priority population (other chromosomal abnormalities other than Down syndrome, intellectual disability, congenital anomalies and conditions that cause disability with microcephaly), as well as the caregivers of people with this type of conditions. Vaccination in children with this type of disorders should be considered as part of the first priority group, once safe vaccines against SARS-CoV-2 are available for use in children and adolescents.

Skeletal dysplasias in Latin America.

Skeletal dysplasias (SD) are disturbances in growth due to defects intrinsic to the bone and/or cartilage, usually affecting multiple bones and having a progressive character. In this article, we review the state of clinical and research SD resources available in Latin America, including three specific countries (Brazil, Argentina, and Chile), that have established multidisciplinary clinics for the care of these patients. From the epidemiological point of view, the SD prevalence of 3.2 per 10,000 births from nine South American countries included in the ECLAMC network represents the most accurate estimate not just in Latin America, but worldwide. In Brazil, there are currently five groups focused on SD. The data from one of these groups including the website www.ocd.med.br, created to assist in the diagnosis of SD, are highlighted showing that telemedicine for this purpose represents a good strategy for the region. The experience of more than 30 years of the SD multidisciplinary clinic in an Argentinian Hospital is presented, evidencing a solid experience mainly in the follow-up of the most frequent SD, especially those belonging the FGFR3 group and OI. In Chile, a group with 20 years of experience presents its work with geneticists and pediatricians, focusing on diagnostic purposes and clinical management. Altogether, although SD health-care and research activities in Latin America are in their early stages, the experience in these three countries seems promising and stimulating for the region as a whole.

Diagnóstico prenatal de malformaciones congénitas y alteraciones cromosómicas: resultado de la experiencia CIMAF - Hospital Dr. Sótero Del Río / Prenatal Diagnosis of Congenital Malformations and Chromosomal Abnormalities: Single Center Experience - Hospital Dr. Sótero Del Río, Chile

INTRODUCCIÓN: El diagnóstico prenatal de anomalías congénitas tiene como objetivo ofrecer consejería apropiada, identificar aquellas patologías que se benefician de terapia fetal y coordinar la derivación de estas pacientes a centros terciarios para un óptimo manejo perinatal. Para el diagnóstico y manejo de las anomalías congénitas en el Hospital Dr. Sótero Del Río contamos con un equipo multidisciplinario. El objetivo de este estudio es describir nuestra experiencia como centro de referencia en Santiago de Chile en relación al diagnostico prenatal de malformaciones congénitas, estudio genético prenatal y resultados perinatales. MÉTODOS: Estudio retrospectivo y descriptivo. Se incluyó a las pacientes registradas en las bases de datos ecográficas entre 2010 y 2019 del Hospital Dr. Sotero del Rio. Se revisaron fichas clínicas para evaluación y seguimiento postnatal. RESULTADOS: Se evaluaron 404 pacientes con sospecha de malformaciones congénitas o marcadores de aneuploidías. La edad gestacional media de la evaluación fue 29 semanas (14-38 semanas). La mediana de la edad gestacional al parto fue 37.6 semanas (20-41 semanas). Se obtuvo un 78% de recién nacidos vivos, 12% óbitos fetales y 10% mortineonatos. Las malformaciones más frecuentes fueron cardiovasculares, sistema nervioso central, hidrops, extremidades, abdomen y genitourinario. Se realizo el estudio genético en 232 pacientes; 61% resultado normal, 12.5% trisomía 21, 8% trisomía 18, 4% trisomía 13, 4% XO, 4% otras. Se analizaron las pacientes que se acogieron a la ley de interrupción voluntaria del embarazo. CONCLUSIÓN: Destacamos la importancia de derivación a centros de referencia de pacientes con sospecha de malformaciones congénitas para un adecuado diagnostico prenatal, ofrecer un manejo con equipo multidisciplinario y así mejorar los resultados neonatales.

INTRODUCTION: The objectives of prenatal diagnosis of fetal malformations are to offer the patient and her family the proper counseling, identify those conditions that benefits of prenatal therapy and to coordinate the referral to tertiary centers to improve neonatal survival. Our hospital counts with a multidisciplinary team who evaluate the patients together. The objective of this study is to describe our experience as a referral center in prenatal diagnosis, management and neonatal outcomes in Santiago de Chile. METHODS: Retrospective and descriptive study. Patients registered in our prenatal diagnosis database between September 2010 and July 2019 were included. Clinical files were reviewed for neonatal outcomes. OUTCOMES: 404 patients with congenital malformations or aneuploidy markers were evaluated. The average gestational age of the evaluation was 29 weeks. Median gestational age to delivery was 37 weeks plus 6 days. 78% of livebirth, 12% fetal demise and 10% of neonatal death were obtained. The most frequent fetal malformations were cardiovascular, central nervous system, fetal hydrops, extremities, abdominal wall defects and urinary system. Fetal karyotype was performed in 232 patients; 61% normal karyotype, 12.5% trisomy 21, 8% trisomy 18, 4% trisomy 13, 4% monosomy X, 4% others. We also analyze the patients who agreed to termination of pregnancy according to Chilean legislation. CONCLUSION: We highlight the importance of referral of patients with suspected fetal malformations to tertiary centers for an adequate evaluation by a multidisciplinary team of specialists, to improve the survival and neonatal outcome.

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.

Autosomal 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.

HIST1H1E heterozygous protein-truncating variants cause a recognizable syndrome with intellectual disability and distinctive facial gestalt: A study to clarify the HIST1H1E syndrome phenotype in 30 individuals.

Histone Gene Cluster 1 Member E, HIST1H1E, encodes Histone H1.4, is one of a family of epigenetic regulator genes, acts as a linker histone protein, and is responsible for higher order chromatin structure. HIST1H1E syndrome (also known as Rahman syndrome, OMIM #617537) is a recently described intellectual disability (ID) syndrome. Since the initial description of five unrelated individuals with three different heterozygous protein-truncating variants (PTVs) in the HIST1H1E gene in 2017, we have recruited 30 patients, all with HIST1H1E PTVs that result in the same shift in frame and that cluster to a 94-base pair region in the HIST1H1E carboxy terminal domain. The identification of 30 patients with HIST1H1E variants has allowed the clarification of the HIST1H1E syndrome phenotype. Major findings include an ID and a recognizable facial appearance. ID was reported in all patients and is most frequently of moderate severity. The facial gestalt consists of a high frontal hairline and full lower cheeks in early childhood and, in later childhood and adulthood, affected individuals have a strikingly high frontal hairline, frontal bossing, and deep-set eyes. Other associated clinical features include hypothyroidism, abnormal dentition, behavioral issues, cryptorchidism, skeletal anomalies, and cardiac anomalies. Brain magnetic resonance imaging (MRI) is frequently abnormal with a slender corpus callosum a frequent finding.

Partial microduplication in the histone acetyltransferase complex member KANSL1 is associated with congenital heart defects in 22q11.2 microdeletion syndrome patients.

22q11.2 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.

Proximal Deletion of 6q Overlapping with Toriello-Carey Facial Phenotype: Prenatal Findings, Clinical Course, Differential Diagnosis, and Review.

Proximal 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.

Chromosomal microarrays testing in children with developmental disabilities and congenital anomalies / Análise cromossômica por microarray em crianças com deficiências de desenvolvimento e anomalias congênitas

OBJECTIVES: 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(tm) 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. .

OBJETIVO: O uso clínico de técnicas baseadas em microarrays para a análise de transtornos de desenvolvimento tem surgido durante a última década. Assim, o microarray cromossômico tem sido posicionado como um teste de primeiro nível clínico. Relatamos a primeira experiência em uma coorte chilena. MÉTODOS: Pacientes chilenos com atraso de desenvolvimento e anomalias congênitas foram estudados com um microarray de alta densidade (CytoScan(tm) HD Array, Affymetrix, Inc., Santa Clara, CA, EUA). Pacientes tiveram estudos citogenéticos anteriores, ou um resultado normal ou de uma anomalia não bem caracterizada. RESULTADOS: Foram analisados 40 pacientes selecionados por dois ou mais critérios, incluindo: anomalias congênitas maiores, dismorfismo facial, atraso de desenvolvimento e deficiência intelectual. Uma variante do número de cópia (CNV) foi encontrada em 72,5% dos pacientes, enquanto que uma CNV patogênica foi encontrada em 25% dos pacientes e uma CNV de significado clínico incerto foi encontrada em 2,5% dos pacientes. CONCLUSÕES: A análise cromossômica microarray é uma ferramenta útil e poderosa em transtornos de desenvolvimento, permite um diagnóstico preciso, melhora a taxa de diagnóstico e descobre novas etiologias. O custo mais elevado é uma limitação para um uso difundido em nossa realidade. .

Chromosomal microarrays testing in children with developmental disabilities and congenital anomalies.

OBJECTIVES: 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.

Case fatality rate and associated factors in patients with 22q11 microdeletion syndrome: a retrospective cohort study.

OBJECTIVE: 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.

Medical genetics and genetic counseling in Chile.

In 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.

Palate abnormalities in Chilean patients with chromosome 22q11 microdeletion syndrome.

OBJECTIVE: 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.

Growth in Chilean infants with chromosome 22q11 microdeletion syndrome.

Chromosome 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.