Next-generation sequencing reveals a new mutation in the LTBP2 gene associated with microspherophakia in a Spanish family

Laura Alías, Jaume Crespi, Lidia González-Quereda, Jesús Téllez, Elisabeth Martínez, Sara Bernal, Ma Pia Gallano

Microspherophakia is a rare autosomal recessive eye disorder characterized by small spherical lens. It may present as an isolated finding or in association with other ocular and/or systemic disorders. This clinical and genetic heterogeneity requires the study of large genes (ADAMTSL4, FBN1, LTBP2, ADAMTSL-10 and ADAMTSL17). The purpose of the present study is to identify the genetic cause of this pathology in a consanguineous Spanish family. A clinical exome sequencing experiment was executed by the TruSight One® Sequencing Panel (TSO) from Illumina©. Sanger sequencing was used to validate the NGS results. Only the insertion of an adenine in exon 36 of the LTBP2 gene (c.5439_5440insA) was associated with pathogenicity. This new mutation was validated by Sanger sequencing and segregation analysis was also performed. Haplotype analyses using the polymorphic markers D14S1025, D14S43 and D14S999 close to the LTBP2 gene indicated identity by descent in this family. We describe the first case of a microspherophakia phenotype associated with a novel homozygous mutation in the LTBP2 gene in a consanguineous Caucasian family by means of NGS technology.