Molecular analysis of exons 8, 9 and 10 of the fibroblast growth factor receptor 2 (FGFR2) gene in two families with index cases of Apert Syndrome / Análisis molecular de los exones 8, 9 y 10 del gen del factor de crecimiento de fibroblastos (FGFR2) en dos familias con casos índice de síndrome de Apert

Introduction: Apert syndrome (AS) is a craniosynostosis condition caused by mutations in the Fibroblast Growth Factor Receptor 2 (FGFR2) gene. Clinical features include cutaneous and osseous symmetric syndactily in hands and feet, with variable presentations in bones, brain, skin and other internal organs. Methods: Members of two families with an index case of Apert Syndrome were assessed to describe relevant clinical features and molecular analysis (sequencing and amplification) of exons 8, 9 and 10 of FGFR2 gen. Results: Family 1 consists of the mother, the index case and half -brother who has a cleft lip and palate. In this family we found a single FGFR2 mutation, S252W, in the sequence of exon 8. Although mutations were not found in the study of the patient affected with cleft lip and palate, it is known that these diseases share signaling pathways, allowing suspected alterations in shared genes. In the patient of family 2, we found a sequence variant T78.501A located near the splicing site, which could interfere in this process, and consequently with the protein function.

Introducción: El síndrome Apert (SA) es un síndrome que cursa con craneosinostosis el cual es ocasionado por mutaciones en el gen del Receptor 2 del Factor de Crecimiento de Fibroblastos (FGFR2). Se caracteriza clínicamente por presentar sindactilias cutáneas y óseas en manos y pies de forma simétrica, cursa además con manifestaciones variables esqueléticas, cerebrales, en piel y otros órganos internos. Métodos: Miembros de dos familias con caso índice de Síndrome Apert fueron evaluados con el objetivo de describir las características clínicas relevantes y el análisis molecular (secuenciación y amplificación) de los exones 8, 9 y 10 del gen FGFR2. Resultados: La familia 1 está constituida por la madre, el caso índice y un medio hermano que presenta labio y paladar hendido. En esta familia solo se encontró la mutación S252W en la secuencia del exón 8 del gen FGFR2 del caso índice. A pesar no encontrarse mutaciones dentro del estudio realizado al paciente afectado con labio y paladar hendido, se conoce que estas patologías comparten vías de señalización, lo que permite sospechar alteraciones en genes compartidos. En la familia 2, el resultado molecular del caso índice reportó la variante T78.501A en la secuencia del intrón 8, la cual se sitúa cercana al sitio de splicing, pudiendo alterar este proceso con una consecuente alteración de la función de la proteína.

A case of Apert's Syndrome(Acrocophalosyndactyly) with Fibroblast Growth Factor Receptor 2 Exon IIIa Mutation

Apert syndrome is an uncommon congenital disorder characterized by malformation of the skull in association with symmetrical syndactyly of both hands and feet. This syndrome is autosornal dominant. The original description was presented by Apert in 1906. Since then more than 200 cases have been reported in the world. Recently, we experienced a case of newhorn male infant with congenital anomalies of the skull and extremities. Molecular biologically, he was found to have Ser252Try mutation in the FGFR2 exonIIIa. A brief review of literature was made.

A Case of FGFR2 Exon lllc Mutation in Crouzon Syndrome

Crouzon syndrome, an autosomal dominant disorder, has characteristic features of craniosynostosis, hypertelorism, exophthalmos, maxillary hypoplasia and relative mandibular prognathism. Mutations of fibroblast growth factor receptor 2 (FGFR2) gene are associated with craniosynostotic conditions, such as Crouzon syndrome, Jackson-Weiss syndrome, Pfeiffer syndrome, Apert syndrome and Beare-Stevenson cutis gyrata. We found one child with common morphological features of Crouzon syndrome. Interestingly, she was found to have Cys342Ser mutation in FGFR2 exon lllc which has been previously observed in Jackson-Weiss syndrome. This finding supports the variable expression of FGFR2 in human and allelic heterogeneity in these apparently clinically distinct craniosynostotic conditions.