Complete blood count differences in a cohort of Down syndrome neonates with transient abnormal myelopoiesis screened for GATA1 pathogenic variants.

Transient abnormal myelopoiesis (TAM) raises the risk for acute myeloid leukemia of Down syndrome (DS) (ML-DS), and both are related to GATA1 pathogenic variants. Here, we analyzed which findings on complete blood count (CBC) are associated with TAM in a cohort of neonates with DS screened for GATA1 pathogenic variants. The CBCs were compared among 70 newborns with DS, including 16 patients (22.9%) with TAM (cases), and 54 patients (77.1%) without TAM (controls). TAM was defined as peripheral circulating blasts (PCBs) ≥ 1%. PCR and direct sequencing were used to screen DNA samples from peripheral blood for GATA1 exon 2 mutations. Multivariate logistic regression analyses determined that the mean count of lymphocytes was significantly higher in DS infants with TAM (p = .035) and that lymphocytosis confers a risk for TAM (adjusted odds ratio = 7.23, 95% confidence intervals: 2.02-25.92). Pathogenic variants of GATA1 were identified in 2 of 70 analyzed DS neonates (2.9%), of which one had ML-DS and another had an asymptomatic TAM. Among those DS infants with TAM, the GATA1 pathogenic variant detection was 12.5%. Our results indicated that lymphocytosis is associated with TAM in neonates with DS. However, since not all infants with an abnormal CBC had TAM, and not all infants with TAM had GATA1 pathogenic variants, we emphasize that only the search for GATA1 pathogenic variants allows the proper identification of the subgroup of DS infants with a real increasing in risk for ML-DS.

Acute promyelocytic leukemia with PML/RARA (bcr1, bcr2 and bcr3) transcripts in a pediatric patient.

Patients with acute promyelocytic leukemia (APL) exhibit the t(15;17)(q24.1;q21.2) translocation that produces the promyelocytic leukemia (PML)/retinoic acid receptor α (RARA) fusion gene. Different PML breakpoints yield three alternative molecular transcripts, bcr1, bcr2 and bcr3. The present study reports the simultaneous presence of three PML/RARA transcripts in a pediatric female patient diagnosed with APL, according to the clinical characteristics, immunophenotype and karyotype of the patient. The simultaneous presence of the PML/RARA transcripts were detected using reverse transcription-quantitative PCR (RT-qPCR). This was confirmed with HemaVision-28N Multiplex RT-qPCR, HemaVision-28Q qualitative RT-qPCR and the AmpliSeq RNA Myeloid Panel. To the best of our knowledge, the pediatric patient described in the present study is the first case found to exhibit all three PML/RARA transcripts (bcr1, bcr2 and bcr3). Additionally, a microarray analysis was performed to determine the expression profile, potential predictive biomarkers and the implications of this uncommon finding. According to the information obtained from molecular monitoring, the results reported in the present study were associated with a good patient prognosis. In addition, upregulated genes that are rare in acute myeloid leukemia were identified, and these genes may be promising diagnostic biomarkers for further study. For example, CCL-1 is present in leukemic stem cells, causing treatment failure and relapse, and α- and ß-defensins have been reported exclusively in chronic myeloid leukemia. However, the results of the present study confirmed that they may also be present in APL. Thus, these findings suggested a possible signaling pathway that involves the PML/RARA oncoprotein in APL.

Frequency of chromosome 22q11.2 deletion among newborns with non-syndromic congenital heart defects from western Mexico.

BACKGROUND: Congenital heart defects (CHD) are among the most frequent manifestations of 22q11.2 deletion syndrome. Although we found relatively few studies aimed at specifically detecting 22q11.2 deletion in newborns (NB) with CHD, none of them has been performed in Mexico. METHODS: We conducted a prospective hospital-based study from January 2017 to March 2021 in the Genetics and Pediatric Cardiology Services of the Hospital Civil de Guadalajara Dr. Juan I. Menchaca (Guadalajara, Mexico). All consecutive NBs identified with any non-syndromic major CHD confirmed by echocardiography were eligible to participate. A total of 98 NBs were included, 51 males and 47 females. Fluorescence in situ hybridization (FISH) analysis was conducted to search for deletion of chromosome 22q11.2 in interphase nuclei of standard lymphocyte cultures. RESULTS: We found eight patients (8.2%) with CHD and the 22q11.2 deletion, all of them with conotruncal defects, particularly of the truncus arteriosus (p = 0.013), tetralogy of Fallot (p = 0.024), and pulmonary atresia with ventricular septal defect (p = 0.031) subtypes. With de exception of one infant with hypocalcemia and another with hypocalcemia and thymic aplasia, the diagnosis of 22q11.2 deletion was not clinically suspected in the other patients. CONCLUSIONS: Our results confirm the importance of excluding the presence of the 22q11.2 deletion in every NB with CHDs, particularly of the conotruncal subtype, even in the absence of other manifestations.

INTRODUCCIÓN: Las cardiopatías congénitas (CC) son una de las manifestaciones más frecuentes del síndrome de deleción 22q11.2. A pesar de que existen relativamente pocos estudios dirigidos a detectar específicamente la deleción 22q11.2 en recién nacidos (RN) con CC, ninguno de ellos ha sido realizado en México. MÉTODOS: Se realizó un estudio prospectivo de base hospitalaria desde enero de 2017 hasta marzo de 2021 en los Servicios de Genética y Cardiología Pediátrica del Hospital Civil de Guadalajara Dr. Juan I. Menchaca (Guadalajara, México). Todos los RN consecutivos identificados con cualquier tipo de CC mayor no sindrómica confirmada por ecocardiografía fueron elegibles para participar. Se incluyeron 98 recién nacidos, 51 de sexo masculino y 47 de sexo femenino. Mediante el análisis de hibridación fluorescente in situ (FISH, por sus siglas en inglés) se realizó la búsqueda de la deleción del cromosoma 22q11.2 en núcleos en interfase de cultivos de linfocitos estándar. RESULTADOS: Se encontraron ocho pacientes (8.2%) con CC y la deleción 22q11.2, todos ellos con defectos conotruncales, particularmente de los subtipos tronco arterioso (p = 0.013), tetralogía de Fallot (p = 0.024) y atresia pulmonar con comunicación interventricular (p = 0.031). Con excepción de un lactante con hipocalcemia y otro con hipocalcemia y aplasia tímica, el diagnóstico de deleción 22q11.2 no se sospechó clínicamente en los demás pacientes. CONCLUSIONES: Los resultados de este trabajo confirman la importancia de excluir la presencia de la deleción 22q11.2 en todos los RN con CC, particularmente del subtipo conotruncal, incluso en ausencia de otras manifestaciones.

Frequency of chromosome 22q11.2 deletion among newborns with non-syndromic congenital heart defects from western Mexico / Frecuencia de la deleción del cromosoma 22q11.2 en recién nacidos con cardiopatías congénitas no sindrómicas del occidente de México

Abstract Background: Congenital heart defects (CHD) are among the most frequent manifestations of 22q11.2 deletion syndrome. Although we found relatively few studies aimed at specifically detecting 22q11.2 deletion in newborns (NB) with CHD, none of them has been performed in Mexico. Methods: We conducted a prospective hospital-based study from January 2017 to March 2021 in the Genetics and Pediatric Cardiology Services of the Hospital Civil de Guadalajara Dr. Juan I. Menchaca (Guadalajara, Mexico). All consecutive NBs identified with any non-syndromic major CHD confirmed by echocardiography were eligible to participate. A total of 98 NBs were included, 51 males and 47 females. Fluorescence in situ hybridization (FISH) analysis was conducted to search for deletion of chromosome 22q11.2 in interphase nuclei of standard lymphocyte cultures. Results: We found eight patients (8.2%) with CHD and the 22q11.2 deletion, all of them with conotruncal defects, particularly of the truncus arteriosus (p = 0.013), tetralogy of Fallot (p = 0.024), and pulmonary atresia with ventricular septal defect (p = 0.031) subtypes. With de exception of one infant with hypocalcemia and another with hypocalcemia and thymic aplasia, the diagnosis of 22q11.2 deletion was not clinically suspected in the other patients. Conclusions: Our results confirm the importance of excluding the presence of the 22q11.2 deletion in every NB with CHDs, particularly of the conotruncal subtype, even in the absence of other manifestations.

Resumen Introducción: Las cardiopatías congénitas (CC) son una de las manifestaciones más frecuentes del síndrome de deleción 22q11.2. A pesar de que existen relativamente pocos estudios dirigidos a detectar específicamente la deleción 22q11.2 en recién nacidos (RN) con CC, ninguno de ellos ha sido realizado en México. Métodos: Se realizó un estudio prospectivo de base hospitalaria desde enero de 2017 hasta marzo de 2021 en los Servicios de Genética y Cardiología Pediátrica del Hospital Civil de Guadalajara Dr. Juan I. Menchaca (Guadalajara, México). Todos los RN consecutivos identificados con cualquier tipo de CC mayor no sindrómica confirmada por ecocardiografía fueron elegibles para participar. Se incluyeron 98 recién nacidos, 51 de sexo masculino y 47 de sexo femenino. Mediante el análisis de hibridación fluorescente in situ (FISH, por sus siglas en inglés) se realizó la búsqueda de la deleción del cromosoma 22q11.2 en núcleos en interfase de cultivos de linfocitos estándar. Resultados: Se encontraron ocho pacientes (8.2%) con CC y la deleción 22q11.2, todos ellos con defectos conotruncales, particularmente de los subtipos tronco arterioso (p = 0.013), tetralogía de Fallot (p = 0.024) y atresia pulmonar con comunicación interventricular (p = 0.031). Con excepción de un lactante con hipocalcemia y otro con hipocalcemia y aplasia tímica, el diagnóstico de deleción 22q11.2 no se sospechó clínicamente en los demás pacientes. Conclusiones: Los resultados de este trabajo confirman la importancia de excluir la presencia de la deleción 22q11.2 en todos los RN con CC, particularmente del subtipo conotruncal, incluso en ausencia de otras manifestaciones.