Medicial student, Federal University of Fronteira Sul, Chapecó, SC, Brazil.
Post-doctorate in immunology, Federal University of Fronteira Sul, Chapecó, SC, Brazil.
Clin Med Res. 2022 Mar;20(1):46-51. doi: 10.3121/cmr.2022.1618. Epub 2022 Feb 7.
Cystic fibrosis is a monogenic and autosomal recessive disease. It is caused by mutations in the Cystic Fibrosis Transmembrane Conductance Regulator gene responsible for encoding the CFTR protein. Involvement of the gastrointestinal and respiratory systems is the main clinical manifestation. In this case, we report a heterozygous patient harboring class I (p.Gly542*) and class V (c.2657+5G>A) mutations. The importance of this case report lies in the clinical features because the patient, aged 3 years, presented with early exocrine pancreatic insufficiency, which can be considered atypical, as most individuals with this genotype are pancreatic sufficient or develop pancreatic insufficiency later in life. This report aims at presenting the tests requested that contributed to the patient's diagnosis, as well as at understanding the association between these mutations and their phenotypic presentation. Interpretation of the genotype-phenotype relationship represents a challenge, as genetic analysis alone is not sufficient to clearly predict severity of the disease. This is because the significant phenotypic heterogeneity existing among patients with the same genotype may exert socioeconomic and sociocultural influences, or by the action of modifiers, such as environmental and modifying genes, which can alter the protein's function and exert an impact on the individual's phenotype.
囊性纤维化是一种单基因常染色体隐性遗传病。它是由编码 CFTR 蛋白的囊性纤维化跨膜电导调节因子基因的突变引起的。胃肠道和呼吸系统的受累是其主要临床表现。在本病例中，我们报告了一名携带 I 类（p.Gly542*）和 V 类（c.2657+5G>A）突变的杂合子患者。本病例报告的重要性在于其临床表现，因为该患者年龄为 3 岁，表现为早期外分泌胰腺功能不全，这可能是非典型的，因为大多数具有这种基因型的个体胰腺功能正常，或在以后的生活中才会发展为胰腺功能不全。本报告旨在介绍有助于患者诊断的检查，并了解这些突变与表型表现之间的关联。对基因型-表型关系的解释是一项挑战，因为仅进行基因分析不足以明确预测疾病的严重程度。这是因为具有相同基因型的患者之间存在显著的表型异质性，可能受到社会经济和社会文化的影响，或者受到修饰因子（如环境和修饰基因）的影响，这些因素可以改变蛋白质的功能并对个体的表型产生影响。
