Genotype and Phenotype Characterization of Patients with Mucopolysaccharidosis IV-A in Chile.

Introduction: Morquio syndrome or mucopolysaccharidosis type IV-A (MPS IV-A) is an autosomal recessive disease caused by biallelic variants in the GALNS gene, encoding the lysosomal enzyme GalN6S, responsible for glycosaminoglycan keratan sulfate and chondroitin-6-sulfate degradation. Studies have shown that the degree of evolutionary and chemical divergence of missense variants in GalN6S when compared to ancestral amino acids is associated with the severity of the syndrome, suggesting a genotype-phenotype correlation. There is little information on Latin American patients with MPS IV-A that replicate these findings. This study aimed to characterize the phenotype and genotype from patients with MPS IV-A, who are under Enzyme Replacement Therapy at the Children's Neuropsychiatry Service of the Hospital Clínico San Borja Arriarán, Santiago, Chile, and to determine if there is any association between genotype and phenotype with those findings. Methods: Information was collected from medical charts, all patients went through a GalN6S enzymatic activity measurement in leukocytes from peripheral blood, and the GALNS gene was sequenced for all cases. Results: 12 patients with MPS IV-A were recruited, all patients presented multisystem involvement, mostly skeletal, and 75% of cases underwent surgical interventions, and cervical arthrodesis was the most frequent procedure. In regards of the genotype, the two most frequent variants were c.319+2T>C (n = 10, 41.66%) and p.(Arg386Cys) (n = 8, 33.33%), the first one was previously described in 2018 in a patient from Chile [Bochernitsan et al., 2018]. Conclusion: This is the first time that a genotype-phenotype correlation has been studied by analyzing the variants effect on the molecular structure of human GalN6S and the evolutionary conservation degree of affected residues in a cohort of patients in Chile. Albeit our work could not find statistically significant associations, we may infer that the evolutionary conservations of affected amino acids and the effect of variants on enzyme structure may play a main role. Further analyzes should consider a meta-analysis of published cases with genotype data and larger samples and include other variables that could provide more information. Finally, our data strongly suggest that variant c.319+2T>C could have a founder effect in Chilean patients with MPS IV-A.

Descripción clínica y hallazgos polisomnográficos en tres pacientes con Síndrome de Treacher Collins / Clinical description and polysomnographic findings in three patients with Treacher Collins

El Síndrome de Treacher Collins (STC) es una enfermedad congénita del desarrollo craneofacial, siendo una complicación frecuente la obstrucción de la vía aérea. Objetivo: Describir clínicamente tres casos de STC y sus hallazgos polisomnográficos. Diseño: Estudio observacional, descriptivo y retrospectivo. Revisión de fichas clínicas y polisomnografías (PSG). Resultados: Se incluyeron tres pacientes con STC, de 1, 17 y 20 años, dos hombres. Todos presentaron malformaciones faciales compatibles con el STC. El paciente menor tuvo apneas desde el nacimiento. En las PSG, todos presentaron eficiencia del sueño disminuida e índice de microdespertares aumentado. Solo un paciente tuvo diagnóstico de Síndrome de Apnea/Hipoapnea Obstructiva del Sueño (SAHOS) severo. Conclusiones: Aún cuando las anomalías craneofaciales no difirieron entre los pacientes, hubo sólo un caso de SAHOS severo. Las otras alteraciones descritas en la PSG afectan la calidad de vida, siendo relevante la búsqueda activa de trastornos respiratorios del sueño en estos pacientes.

Treacher Collins Syndrome (STC) is a congenital craniofacial disorder, being the airway obstruction a frequent complication. Objective: To describe clinical and polysomnographic findings of three cases with STC. Methods: An observational, descriptive and retrospective study. Review of clinical records and nocturnal polysomnography was carried out. Results: Three patients with STC were included of 1, 17 and 20 years old, two were males. All of them with facial malformations compatible with STC. Only the youngest presented apneas since birth. All patients had decreased sleep efficiency and increased arousal index. Only one patient presented with severe Obstructive Sleep Apnea Syndrome (OSAS). Conclusions: Despite the fact that all the patients had similar craniofacial anomalies, only one presented with severe OSAS. The other abnormalities described in the polysomnography affect the quality of life, being relevant performing an active screening of breathing-related sleep disorders in these patients.

Hypomyelination and Congenital Cataract: Identification of a Novel likely pathogenic c.414+1G>A in FAM126A gene Variant.

It is key to expand the differential diagnosis and consider possible genetic etiologies on a patient with congenital cataracts associated with clinical features, such as leukodystrophy or polyneuropathy.

Pediatric Arterial Ischemic Stroke: Clinical Presentation, Risk Factors, and Pediatric NIH Stroke Scale in a Series of Chilean Patients.

Stroke is an important cause of morbidity and mortality in children. Clinical presentation is diverse, and multiple risk factors have been described. The aim of this retrospective study is to describe the clinical presentation, risk factors, and the Pediatric National Institute of Health Stroke Scale (PedNIHSS) in a series of pediatric Chilean patients with the diagnosis of arterial ischemic stroke (AIS). Children diagnosed with AIS aged between 29 d and 18 y were enrolled (1989 to 2016). Clinical characteristics and risk factors were described. PedNIHSS severity score was estimated for patients older than 4 mo of age. Sixty-two patients were included, 66% were male, and the mean age of presentation was 3.5 y. Seventy-nine percent presented motor deficit, 45% seizures, and 15% consciousness impairment. Eighty-two percent had a unilateral stroke and 73% had anterior circulation territory affected. The main risk factors were arteriopathy (63%) and infection (43%). The PedNIHSS mean was 7.6, ranging between 0 and 17. In the categories in which it was possible to apply χ2 test, only the acute systemic conditions category was statistically significant (P = 0.03), being higher in the group of patients younger than 3 y old. We confirmed male predominance in AIS and the most frequent presenting symptom was motor deficit. We found at least 1 risk factor in all patients with complete information. We confirmed arteriopathy as the most frequent risk factor, and acute systemic conditions were higher in patients younger than 3 y old with statistical significance (P = 0.03). The majority of patients presented mild to moderate severity in the PedNIHSS score.

Risk Factors for Perinatal Arterial Ischemic Stroke: A Case-Control Study.

INTRODUCTION: Arterial ischemic stroke in newborns is an important cause of neonatal morbidity and mortality. Its pathophysiology and associated risk factors are not yet clearly understood and defined. OBJECTIVE: The aim of this retrospective study was to investigate possible risk factors in diagnosed cases of PAIS (perinatal arterial ischemic stroke). MATERIALS AND METHODS: Case-control study. Clinical data of patients with PAIS diagnosis were analyzed. Two healthy controls were selected for each PAIS case, matched for gestational age. Risk factors were explored using univariable and multivariable analysis. OUTCOME: 40 patients were included in the study, 24 males and 16 females; 52.5% of cases were diagnosed within the first month of birth, and 47.5% were retrospectively diagnosed. The results showed a male predominance (66.7%). The distribution of cerebral ischemic injury was predominantly medial cerebral artery (87.5%) and occurred more commonly in the left cerebral hemisphere (62.5%). Significant risk factors in the univariate analysis (P < 0.05) were primiparity, stillbirth, neonatal sepsis, asphyxia, twin pregnancy, placenta abruption, emergency cesarean section, Apgar score ≤7 after 5 min, breech presentation, and hyperbilirubinemia. In the multivariate analysis, primiparity (OR 11.74; CI 3.28-42.02), emergency cesarean section (OR 13.79; CI 3.51-54.13), birth asphyxia (OR 40.55; CI 3.08-532.94) and Apgar score ≤7 after 5 min (OR 13.75; CI 1.03-364.03) were significantly associated factors with PAIS. Only five (16.6%) patients had an abnormal thrombophilia study. CONCLUSION: Risk factors of primiparity, emergency cesarean section, birth asphyxia, and Apgar score ≤7 after 5 min were significantly associated with perinatal stroke. More studies with a larger number of patients and with prolonged follow up are required to establish more clearly the associated risk factors involved in this pathology.