WNT1 mutations in families affected by moderately severe and progressive recessive osteogenesis imperfecta.

Osteogenesis imperfecta (OI) is a heritable disorder that ranges in severity from death in the perinatal period to an increased lifetime risk of fracture. Mutations in COL1A1 and COL1A2, which encode the chains of type I procollagen, result in dominant forms of OI, and mutations in several other genes result in recessive forms of OI. Here, we describe four recessive-OI-affected families in which we identified causative mutations in wingless-type MMTV integration site family 1 (WNT1). In family 1, we identified a homozygous missense mutation by exome sequencing. In family 2, we identified a homozygous nonsense mutation predicted to produce truncated WNT1. In family 3, we found a nonsense mutation and a single-nucleotide duplication on different alleles, and in family 4, we found a homozygous 14 bp deletion. The mutations in families 3 and 4 are predicted to result in nonsense-mediated mRNA decay and the absence of WNT1. WNT1 is a secreted signaling protein that binds the frizzled receptor (FZD) and the coreceptor low-density lipoprotein-receptor-related protein 5 (LRP5). Biallelic loss-of-function mutations in LRP5 result in recessive osteoporosis-pseudoglioma syndrome with low bone mass, whereas heterozygous gain-of-function mutations result in van Buchem disease with elevated bone density. Biallelic loss-of-function mutations in WNT1 result in a recessive clinical picture that includes bone fragility with a moderately severe and progressive presentation that is not easily distinguished from dominant OI type III.

Dysmorphic features and congenital heart disease in chromosome 6q deletion: A short report.

In this report, we describe a one and a half year old girl showing terminal deletion of long arm of chromosome 6q. The associated abnormalities such as congenital heart disease, mental retardation, and dysmorphic features are described. Cytogenetic studies with GTG banding showed 46,XX,del(6)(q24→qter). Karyotype of the parents was normal suggesting a denovo event.

Case Report: Whole exome sequencing reveals a novel frameshift deletion mutation p.G2254fs in COL7A1 associated with autosomal recessive dystrophic epidermolysis bullosa.

Dystrophic epidermolysis bullosa simplex (DEB) is a phenotypically diverse inherited skin fragility disorder. It is majorly manifested by appearance of epidermal bullae upon friction caused either by physical or environmental trauma. The phenotypic manifestations also include appearance of milia, scarring all over the body and nail dystrophy. DEB can be inherited in a recessive or dominant form and the recessive form of DEB (RDEB) is more severe. In the present study, we identify a novel p.G2254fs mutation in COL7A1 gene causing a sporadic case of RDEB by whole exome sequencing (WES). Apart from adding a novel frameshift Collagen VII mutation to the repertoire of known mutations reported in the disease, to the best of our knowledge, this is the first report of a genetically characterized case of DEB from India.