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Andrea L Vincent

Publications and source records attributed to Andrea L Vincent.

8 recordsLinked to original sources
PubMed2006

An investigation into FOXE1 polyalanine tract length in premature ovarian failure.

Premature ovarian failure (POF) is a common condition affecting 1% of women worldwide. There is strong evidence for genetic involvement in POF as many cases are familial, and mutations in several genes have been associated with POF. We investigated variation in FOXE1 polyalanine tract length, following the observation that polyalanine tract deletions are seen in the closely related FOXL2 in patients with POF. In addition, polyalanine tract expansions in FOXL2 are often seen in patients with blepharophimosis-ptosis-epicanthus inversus syndrome (BPES), a rare eyelid disorder often associated with POF. The FOXE1 polyalanine tract shows marked variation in its length between POF patients and normal controls, existing as an allele of 12, 14, 16, 17 or 19 alanine residues. We found evidence to suggest that variation in FOXE1 polyalanine tract length predisposes to POF.

Adult↗
PubMed2005

Computerized corneal topography in a paediatric population with Down syndrome.

PURPOSE: To characterize abnormal corneal topographic changes using corneal computerized videokeratography (CVK) in a paediatric population with Down syndrome, and in their parents. METHODS: Prospective, non-randomized clinical trial. Twenty-one children with Down syndrome (mean age 6.9 years) recruited from The Hospital for Sick Children, 18 of their parents, and a paediatric control group of 60 otherwise well children (mean age 9 years), underwent complete ocular examination and CVK using the EyeSys system. Corneal topographic maps were assessed subjectively, and three objective parameters analysed: central corneal power (CP), difference in central corneal power between the two eyes (DCP), and inferior-superior steepening asymmetry (I-S). RESULTS: Corneal curvature in children with Down syndrome was significantly steeper than in the paediatric control population (CP 46.66 vs 42.60 D, P <0.0001), but changes with age paralleled that of the control population. DCP and I-S values were also significantly different from the control population (P <0.0001). 39% of the parents of children with Down syndrome had at least one abnormal parameter. CONCLUSIONS: This study demonstrates that CVK is a useful tool in the ocular assessment of patients with Down syndrome. The findings suggest that this patient population have abnormalities of corneal shape even in the absence of clinical evidence of keratoconus. A greater than expected incidence of abnormal topographic changes was observed in the parents of these patients.

Adolescent↗
PubMed2005

Inherited corneal disease: the evolving molecular, genetic and imaging revolution.

Advances in molecular genetics and in vivo ocular imaging modalities have enhanced our understanding of the corneal dystrophies. To date at least 11 genes have been identified, in which mutations manifest in corneal disease. In addition there are at least eight other loci identified to which corneal dystrophies have been linked. The information gained from the knowledge of gene function, aberrant protein production, or altered enzyme activity in the cornea, has resulted in greater knowledge of the pathophysiological mechanisms in these disorders. In vivo confocal microscopy has recently enabled microstructural study of dystrophic corneas throughout the disease course, rather than being limited to histopathological analysis of tissue removed at corneal transplantation. This perspective article summarizes the current knowledge, with emphasis on the genes, mutant proteins and resultant mechanisms that lead to manifestations of disease, along with characteristic findings with in vivo confocal microscopy.

Biomedical Research↗
PubMed2002

VSX1: a gene for posterior polymorphous dystrophy and keratoconus.

We identified mutations in the VSX1 homeobox gene for two distinct inherited corneal dystrophies; posterior polymorphous dystrophy (PPD) and keratoconus. One of the mutation (R166W) responsible for keratoconus altered the homeodomain and impaired DNA binding. Two other sequence changes (L159M and G160D) were associated with keratoconus and PPD, respectively, and involved a region adjacent to the homeodomain. The G160D substitution, and a fourth defect affecting the highly conserved CVC domain (P247R), occurred in a child with very severe PPD who required a corneal transplant at 3 months of age. In this family, relatives with the G160D change alone had mild to moderate PPD, while P247R alone caused no corneal abnormalities. However, with either the G160D or P247R mutation, electroretinography detected abnormal function of the inner retina, where VSX1 is expressed. These data define the molecular basis of two important corneal dystrophies and reveal the importance of the CVC domain in the human retina.

Adult↗
PubMed2002

Digenic inheritance of early-onset glaucoma: CYP1B1, a potential modifier gene.

"Early-onset glaucoma" refers to genetically heterogeneous conditions for which glaucoma manifests at age 5-40 years and for which only a small subset is molecularly characterized. We studied the role of MYOC, CYP1B1, and PITX2 in a population (n=60) affected with juvenile or early-onset glaucoma from the greater Toronto area. By a combination of single-strand conformation polymorphism and direct cycle sequencing, MYOC mutations were detected in 8 (13.3%) of the 60 individuals, CYP1B1 mutations were detected in 3 (5%) of the 60 individuals, and no PITX2 mutations were detected. The range of phenotypic expression associated with MYOC and CYP1B1 mutations was greater than expected. MYOC mutations included cases of juvenile glaucoma with or without pigmentary glaucoma and mixed-mechanism glaucoma. CYP1B1 mutations involved cases of juvenile open-angle glaucoma, as well as cases of congenital glaucoma. The study of a family with autosomal dominant glaucoma showed the segregation of both MYOC and CYP1B1 mutations with disease; however, in this family, the mean age at onset of carriers of the MYOC mutation alone was 51 years (range 48-64 years), whereas carriers of both the MYOC and CYP1B1 mutations had an average age at onset of 27 years (range 23-38 years) (P=.001). This work emphasizes the genetic heterogeneity of juvenile glaucoma and suggests, for the first time, that (1) congenital glaucoma and juvenile glaucoma are allelic variants and (2) the spectrum of expression of MYOC and CYP1B1 mutations is greater than expected. We also propose that CYP1B1 may act as a modifier of MYOC expression and that these two genes may interact through a common pathway.

Adolescent↗
PubMed2002

Prosthetic conformers: a step towards improved rehabilitation of enucleated children.

Enucleation in children is distressing for families, particularly because of concerns of cosmesis. In the last 2 years the authors have used painted conformers instead of clear conformers to make the postoperative healing and rehabilitation period easier on the families. A set of six prosthetic conformers (small, medium and large; blue and brown) was available in the operating room. An appropriately sized and colour-matched conformer was placed in the socket at the end of surgery and kept for an average of 4-6 weeks. This decreased the psychological impact of enucleation, yet achieved the goals of an ideal conformer allowing optimal wound healing without pressure to fit a permanent individualized prosthesis earlier than 6 weeks after surgery. The acceptance of families to prosthetic conformers in this paediatric population has been very positive, improving rehabilitation of the family and the enucleated child.

Eye Enucleation↗