Distichiasis: An update on etiology, treatment and outcomes

Distichiasis, an extra row of eyelashes emerging from meibomian gland orifices, occurs due to the metaplastic transition of sebaceous glands into the pilosebaceous unit. It can present congenitally, such as in lymphedema distichiasis syndrome, or secondary to acquired conditions, such as cicatrizing conjunctivitis, trachoma. This review summarizes the etiology of distichiasis, its presentation, the evolution of various surgical techniques, and their outcomes in human and animal eyes. The published literature has focused on the different treatment modalities and their outcomes; the etiopathogenesis of this condition remains elusive. Truncating mutations (missense, frameshift, and nonsense) in the Forkhead family gene FOXC2 are involved in the distichiasis-lymphedema syndrome. The treatment options are no different for congenital versus acquired distichiasis, with no specific available algorithms. Acquired distichiasis in cicatrizing ocular surface diseases is difficult to manage, and existing treatment options offer success rates of 50%-60%. The outcomes of electroepilation or direct cryotherapy are not as good as surgical excision of distichiatic lashes after splitting the anterior and posterior lamella under direct visualization. The marginal tarsectomy with or without free tarsoconjunctival graft has shown good results in eyes with congenital and acquired distichiasis. The details of differences between normal and distichiatic lash, depth, or course of distichiatic eyelashes remain largely unknown. Studies exploring the distichiatic eyelash depth might improve the outcomes of blind procedures such as cryotherapy or radiofrequency-assisted epilation.

Haploinsufficiencies of FOXF1 and FOXC2 genes associated with lethal alveolar capillary dysplasia and congenital heart disease

Neonatal deaths account for about 67% of all deaths during the first year of life in the USA. Genetic defects are important factors contributing to neonatal deaths and congenital anomalies. Here we report on the identification of a 1.37 Mb de novo deletion of chromosome 16q24.1-q24.2 by microarray-based comparative genomic hybridization (aCGH) technique in a newborn boy with lethal severe alveolar capillary dysplasia and multiple congenital anomalies who died of irreversible pulmonary hypertension, respiratory failure and cor pulmonale at three days of age. The phenotypic findings and causal genes (FOXF1 and FOXC2) involved in producing this unusual syndrome are detailed. Our findings independently confirm the results in a previous publication describing multiple patients with similar clinical and genetic observations, and highlight the importance of scanning human genomes at high resolution for identifications of micro-imbalances as pathogenic causes in neonates with unexplained congenital anomalies. (c) 2010 Wiley-Liss, Inc.