Enfermedad peroxisomal, condrodisplasia rizomelica punctata tipo 1: reporte de caso / Peroxisomal disorder, rhizomelyc chondrodysplasia punctata type 1: case report

Introducción: Las enfermedades peroxisomales son un grupo de trastornos monogénicos que incluyen desórdenes en la biogénesis del peroxisoma o deficiencias enzimáticas. La Condrodisplasia Rizomélica Punctata Tipo 1 (RCDP1) pertenece al primer grupo, es autosómica recesiva originada por mutaciones del gen PEX7, que codifica para el receptor PTS2. El objetivo del presente artículo son describir una enfermedad genética de baja prevalencia, explicando sus principales características y la importancia de la aproximación diagnóstica y asesoría genética. Caso clínico: Lactante masculino de 13 meses, sin antecedentes familiares ni consanguinidad. Al nacimiento presentaba acortamiento de miembros superiores. Fue intervenido a los 7 meses por catarata bilateral. Presentaba severo retardo del crecimiento, retraso del desarrollo psicomotor, anomalías menores craneofaciales, acortamiento rizomélico de miembros superiores y en menor grado de miembros inferiores. En la radiografía se identificaban calcificaciones punteadas del cartílago en rótula. Entre los exámenes de laboratorio destacaba elevación de los ácidos grasos fitánico y pristánico. El paciente falleció a la edad de 3 años. Discusión: Esta es una enfermedad rara, la prevalencia es 1/100.000, se han descrito diferentes mutaciones del gen PEX7 teniendo variación en el fenotipo. El tratamiento es básicamente sintomático y depende de la gravedad de las manifestaciones clínicas, el tipo rizomélico es de mal pronóstico, la mayoría de los pacientes no sobrevive antes de la primera década de vida. La asesoría genética es fundamental ya que se considera un riesgo del 25% de recurrencia.

Introduction: Peroxisomal diseases are a group of monogenic disorders that include defects in peroxisome biogenesis or enzyme dificiencies. Rhizomelic chondrodysplasia punctata type 1 (RCDP1) belongs to the first group, caused by autosomal recessive mutations on PEX7 gene, encoding for PTS2 receptor. The aims of this report are to describe a genetic disease of low prevalence, explaining its main characteristics and the importance of the diagnostic approach and genetic counseling. Case report: 13-month-old male infant with no medical history, family or consanguinity, demonstrate at birth upper limbs shortening. Surgery intervention at seven months old for bilateral cataract. Growth retardation, psychomotor retardation, minor craniofacial anomalies, rhyzomelic shortened upper limbs and lower limbs lesser degree. Punctata calcifications in patella cartilage. Also fatty acid phytanic and pristanic increased levels. Patient dead at age of 3 years. Discussion: RCDP1 is a rare disease, with a prevalence of 1/100,000. Different mutations of PEX7 gene have been described, with variations in phenotype. The treatment is basically symptomatic and depends on the severity of clinical manifestations. The rhizomelic type has poor prognosis, most patients do not survive before the first decade of live. Genetic counseling is essential because it is consider a 25% risk of recurrence.

Fluorescent co-localization of PTS1 and PTS2 and its application in analysis of the gene function and the peroxisomal dynamic in Magnaporthe oryzae / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

The peroxisomal matrix proteins involved in many important biological metabolism pathways in eukaryotic cells are encoded by nucleal genes, synthesized in the cytoplasm and then transported into the organelles. Targeting and import of these proteins depend on their two peroxisomal targeting signals (PTS1 and PTS2) in sequence as we have known so far. The vectors of the fluorescent fusions with PTS, i.e., green fluorescence protein (GFP)-PTS1, GFP-PTS2 and red fluorescence protein (RFP)-PTS1, were constructed and introduced into Magnaporthe oryzae Guy11 cells. Transformants containing these fusions emitted fluorescence in a punctate pattern, and the locations of the red and green fluorescence overlapped exactly in RFP-PTS1 and GFP-PTS2 co-transformed strains. These data indicated that both PTS1 and PTS2 fusions were imported into peroxisomes. A probable higher efficiency of PTS1 machinery was revealed by comparing the fluorescence backgrounds in GFP-PTS1 and GFP-PTS2 transformants. By introducing both RFP-PTS1 and GFP-PTS2 into Deltamgpex6 mutants, the involvement of MGPEX6 gene in both PTS1 and PTS2 pathways was proved. In addition, using these transformants, the inducement of peroxisomes and the dynamic of peroxisomal number during the pre-penetration processes were investigated as well. In summary, by the localization and co-localization of PTS1 and PTS2, we provided a useful tool to evaluate the biological roles of the peroxisomes and the related genes.