Tayebeh Rezaie

Primary non-syndromic lymphoedema (Meige disease) is not caused by mutations in FOXC2

Primary lymphoedema is a genetic disorder with numerous phenotypic subgroups. The most common form is the non-syndromic Meige disease, which is primarily of pubertal or later onset, with oedema clinically indistinguishable from that found in the lymphoedema–distichiasis syndrome. There are also other very rare forms of lymphoedema such as yellow nail syndrome and lymphoedema with ptosis, which are clinically similar to Meige disease. The only causative genes so far identified for the non-congenital primary lymphoedemas are the transcription factor FOXC2, where mutations are known to produce lymphoedema with distichiasis, and SOX18 in the very rare condition hypotrichosis–lymphoedema–telangiectasia. This study has examined FOXC2 gene by sequence analysis in 23 affected individuals with Meige disease. A novel truncating mutation (c.563–584del) was identified in one family and found to segregate with the disease in eight affected relatives over three generations. This deletion creates a frameshift that predicts a premature stop at nucleotide 599 and truncating the normal protein by 38%. Although the affected patient initially selected for mutation screening from this family had lymphoedema without distichiasis, all but one of his affected relatives who carried the FOXC2 mutation did have accessory eyelashes originating from their meibomian glands. This is further confirmation that of the primary lymphoedemas, only lymphoedema with distichiasis is caused by FOXC2 mutations. All forms of post-pubertal lymphoedema need careful phenotyping for distichiasis, which may prove difficult to confirm unless several family members are examined, and cannot ever be assumed to be absent from self-report.

Analysis of rare variants and common haplotypes in the optineurin gene in Swedish glaucoma cases.

Objective: Glaucoma, a leading cause of blindness in the world, is characterized by neuropathy of the retinal ganglion cells and the optic nerve. Recently, sequence alterations in the optineuringene were shown to be associated with the disease in families with primarily normal tension glaucoma. Methods: In the present study, 200 patients with primary open-angle glaucoma, 200 patients with exfoliative glaucoma, and 200 matched controls were tested for alterations in the coding sequences using denaturing high-performance liquid chromatography and sequencing. In addition, single nucleotide polymorphisms distributed throughout the gene were typed and haplotypes were constructed. Results: No disease-causing alterations were found in either of the patient cohorts. The risk-associated allele M98K was found in equal amounts in both patients and controls. Analysis of haplotype frequencies and distribution revealed high haplotype diversity but no differences between patients and controls. Conclusion: These experiments show no association between optineurin and our Swedish cohorts of high-pressure glaucoma cases, either in coding sequence or in haplotype frequency and distribution.

Identification of a novel mutation in the paired domain of PAX3 in an Iranian family with waardenburg syndrome type I.

Waardenburg syndrome Type I (WS1) is an autosomal dominant disorder that has previously been associated with mutations in the PAX3 gene on the 2q35 region. In this study, we used an Iranian WS1 family with seven affected individuals in three generations. The phenotypic characteristics of the family include sensorineural deafness, dystopia canthorum, hypopigmented skin patches of the upper limbs, congenital white forelock, confluent white eyebrows, nonpigmented iris, poliosis, and hypopigmentation of the retina. Herein, we report a previously unidentified single-base substitution in exon II (C?T at position 218) that results in a change of serine to leucine (S73L) in this family. This change was not observed in 100 chromosomes of healthy unrelated individuals. This mutation is within the PAX3 paired domain region, a structure that is highly conserved and implicated in DNA binding. This is the first identification of a PAX3 mutation for this phenotype in the Iranian population. This also provides additional confirmation for the involvement of this gene in the etiology of WS1.

Genetic Screening of Leber Congenital Amaurosis in a Large Consanguineous Iranian Family

The molecular defect of one large consanguineous Iranian kindred with Leber Congenital Amaurosis (LCA) is presented. The phenotype mapped to 17p13.1 (LCA1) and excluded from five other LCA loci. Sequence analysis of the GUCY2D gene identified a novel homozygous missense mutation (I816S) that segregated with the inherited disease-haplotype in six affected, eight parents, and two normal gene carriers. This mutation was absent in three other normal family members and 92 normal control subjects. In silico analysis predicted that alteration of the highly conserved isoleucine residue at position 816 to serine is deleterious by affecting secondary structure of the GUCY2D protein.