Estudio clínico y molecular en una familia con osteocondromatosis múltiple / Clinical and molecular study in a family with multiple osteochondromatosis

Resumen: Se presentan dos casos de una familia con diagnóstico de osteocondromatosis múltiple, el cual fue confirmado por estudio molecular con mutación sin sentido en heterocigosis c.1219C>T, (p.Gln407Stop) en el gen EXT1. En el primer caso, en un paciente se presentó deformidad de Madelung como hallazgo infrecuente y en el otro caso, condrosarcoma como complicación temida, resaltando la variación intrafamiliar, por lo que se recomienda la evaluación individual e interdisciplinaria. Además, ante una entidad genética debe brindarse el adecuado y oportuno asesoramiento genético familiar a todos sus integrantes.

Abstract: We present two cases of a family with the diagnosis of multiple osteochondromatosis, which was confirmed by molecular study with nonsense in heterozygosis mutation c.1219C>T, (p.Gln407Stop) in the EXT1 gene. In these cases, the Madelung deformity was presented in one patient as an uncommon finding and chondrosarcoma as a feared complication in the other case, highlighting intrafamilial variation, which is why individual and interdisciplinary evaluation is recommended. In addition, before a genetic entity should provide adequate and timely family genetic counseling to all its members.

Langer-Giedion Syndrome with 8q23.1–q24.13 Deletion by Complex Three-way Translocation

Langer-Giedion syndrome is a very rare genetic disorder that is caused by the deletion on chromosome 8q24.1, encompassing the TRPS1 and EXT1 genes. We describe a 5-month-old female patient who was admitted to our hospital with clinodactyly and weakness in both thumbs. The patient's karyotype was 46,XX,der(4)t(4;19)(q27;q11),der(8)t(4;8)(q27;q22.3),der(19)t(8;19)(q22.3;q11)del(8)(q23q24.1). Multiplex ligation-dependent probe amplification (MLPA) analysis showed that the patient had a heterozygous deletion, rsa 8q24(P064)x1 and rsa 8q24(P245)x1. Array comparative genomic hybridization (CGH) analysis further revealed three interstitial deletions spanning a total of 13.7 Mb at 8q23.1–q24.13. Based on clinical findings and confirmation by cytogenetic, MLPA, and array CGH analyses, the patient was diagnosed with sporadic Langer-Giedion syndrome with three-way translocations. This is the first case of Langer-Giedion syndrome with complex chromosomal rearrangements in Korea.

Alelo doble mutante en el gen EXT1 no informado previamente en una adolescente con exostosis múltiple hereditaria / Double mutant alleles in the EXT1 gene not previously reported in a teenager with hereditary multiple exostoses

Las formas hereditarias de exostosis múltiple, actualmente denominada EXT1 / EXT2-CDG dentro de los desórdenes congénitos de la glicosilación, son los tumores óseos benignos más comunes y se caracterizan por la formación de lesiones óseas cubiertas de cartílago, localizadas en yuxtaposición a epífisis de huesos largos, aunque, en los casos graves, pueden presentar una amplia distribución. El inicio es variable desde los 2-3 años hasta los 13-15 y presenta una incidencia estimada que va de 1/18 000 a 1/50 000 casos en los países europeos. Se presenta el caso de un doble alelo mutante en el gen EXT1 no informado previamente en una adolescente y su familia con exostosis múltiple hereditaria.

Hereditary forms of multiple exostoses, now called EXT1/EXT2-CDG within Congenital Disorders of Glycosylation, are the most common benign bone tumors in humans and clinical description consists of the formation of several cartilage-capped bone tumors, usually benign and localized in the juxta-epiphyseal region of long bones, although wide body dissemination in severe cases is not uncommon. Onset of the Alelo doble mutante en el gen EXT1 no informado previamente en una adolescente con exostosis múltiple hereditariaDouble mutant alleles in the EXT1 gene not previously reported in a teenager with hereditary multiple exostosesdisease is variable ranging from 2-3 years up to 13-15 years with an estimated incidence ranging from 1/18 000 to 1/50 000 cases in European countries. We present a double mutant alleles in the EXT1 gene not previously reported in a teenager and her family with hereditary multiple exostoses