Genetic variants in Colombian patients with inherited cardiac conditions.

BACKGROUND: Clinical and molecular diagnosis of inherited cardiac conditions is key to find at-risk subjects and avoid preventable deaths. This study aimed to identify genetic variants in a sample of Colombian patients diagnosed with inherited cardiac conditions. METHODS: Next-generation sequencing (Illumina platform) using a 231 gene panel was performed in blood samples of 25 unrelated patients with age disease onset between 9 and 55 years. RESULTS: Genetic testing yield was 52%. Two novel likely pathogenic/ pathogenic variants were found: a DSP nonsense variant in a patient with arrhythmogenic cardiomyopathy and a KCNE1 frameshift variant in two patients with long QT syndrome. Younger individuals (<18 years) had the highest genetic testing yield (66.6%) compared to 50% and 20% in young adults and patients over 40 years, respectively. All subjects affected with long QT syndrome with a severe event while exercising had a positive genetic test. They also had four times more loss of consciousness events and, resuscitated sudden cardiac arrest was more representative. CONCLUSION: This study is the first one undertaken in Colombia to evaluate inherited cardiac conditions. It highlights the need to perform mutational analysis to provide adequate genetic counseling and to be able to identify patients at risk of severe events.

Philadelphia-like acute lymphoblastic leukemia: Characterization in a pediatric cohort in a referral center in Colombia.

BACKGROUND: Philadelphia-like (Ph-like) acute lymphoblastic leukemia (ALL) is a subtype of pediatric leukemia with high risk factors and poor outcome. There are few reports of its prevalence in Latin America. AIM: This study evaluated the frequency and clinical and biological characteristics of Ph-like ALL in a pediatric cancer center in Colombia. METHODS: The Ph-like genetic profile was analyzed by a low-density array (LDA). Samples from patients with Ph-like ALL were analyzed by fluorescent in situ hybridization for cytokine receptor like factor 2 (CRLF2) and ABL proto-oncogene 1, non-receptor tyrosine kinase (ABL1) rearrangements. Copy number variations were assessed by multiplex ligation probe amplification. RESULTS: Data from 121 patients were analyzed. Fifteen patients (12.4%) had Ph-like ALL, and these patients had significantly higher leukocyte counts at diagnosis and higher levels of minimal residual disease on days 15 and 33 of induction than patients without the Ph-like subtype. There were no significant differences in sex, age, or response to prednisone at day 8 between the two groups. CRLF2 rearrangements were identified in eight patients, and ABL1 rearrangements were identified in two patients. Other genetic alterations alone or in combination were identified in 77% of patients, including deletions in cyclin dependent kinase inhibitor 2 A/B (46.2%), IKAROS family zinc finger 1 (38.3%), and paired box 5 (30.8%). CONCLUSIONS: Ph-like ALL had a 12.4% prevalence in our cohort of patients with pediatric ALL. The identification of this group of patients has importance for risk stratification and future targeted therapy.

[Brain-lung-thyroid syndrome in a newborn with deletion 14q12-q21.1]. / Síndrome cerebro-pulmón-tiroides en un recién nacido con deleción 14q12-q21.1.

INTRODUCTION: In newborns with respiratory failure and interstitial lung disease, it should be approached as chILD (Childhood Interstitial Lung Disease) syndrome to rule out alterations in surfactant metabolism and brain-lung-thyroid syndrome caused by pathogenic variants in the NKX2-1 gene. OBJECTIVE: To pre sent a newborn with chILD syndrome and a large deletion in chromosome 14q12-q21.1. CLINICAL CASE: Newborn patient with respiratory distress since birth, chILD syndrome, and hypothyroidism, in which brain-lung-thyroid syndrome was suspected. He also presented seizures, minor and ma jor abnormalities on physical examination. Microarray analysis revealed a 14.7 Mb deletion in the chromosome 14q12-q21.1, which includes the NKX2-1 gene. CONCLUSION: The brain-lung-thyroid syndrome should be considered in newborns with respiratory distress syndrome and diffuse lung disease (chILD syndrome), especially if they present hypotonia, choreoathetosis, or hypothyroidism. Diagnosis confirmation requires genetic analysis, even more, when there are other abnormalities not explained by the suspected syndrome.

Systematic molecular analysis of hemophilia A patients from Colombia.

Hemophilia A (HA) is an X-linked recessive disorder and the second most common coagulation disorder with an incidence of 1 in 5,000 live born males. Worldwide, there are 178,500 affected individuals, 60% with the severe form of the disease. Intron 22 and 1 inversions (Inv22 and Inv1) are the most frequent molecular alterations found in severe HA patients with a frequency of 45-50% and 0.5-5%, respectively. We have implemented a systematic cost-effective strategy for the identification of the molecular alteration in HA patients using Inverse shifting-PCR for Inv22 and Inv1, followed by the analysis of the F8 gene coding region by means of high resolution melting (HRM) PCR and Sanger sequencing in Inv22 and Inv1 negative patients. A total of 33 male HA patients and 6 women were analyzed. Inversion 22 was detected in 14/33 male patients (42.4%), 3/33 (9.1%) had Inv1, 3/33 (9.1%) had large structural variants, and 11/33 (33.3%) single nucleotide/ small frameshift variants. No genetic variant was found in 2/33 patients (6%). With this systematic approach we detected pathogenic variants in 31 out of 33 male affected individuals (94%) tested for the first time.in a cohort of patients from Colombia.