Classic homocystinuria and keratoconus: a case report

ABSTRACT Homocystinuria is one of a group of genetic disorders called inborn errors of metabolism. It is characterized by a deficiency of the enzyme that converts homocysteine to cystathionine. Keratoconus is an ophthalmologic condition characterized by thinning of the corneal stroma, which causes the cornea to assume a conical shape. There is little information in the scientific literature about the association between keratoconus and homocystinuria. We believe that a collagen cross-linking defect may be the key to understand the connection between these two conditions. This case report describes a 38-year-old male patient with a diagnosis of classical homocystinuria since age 13. At the age of 16, he received a diagnosis of asymmetrical keratoconus when referred for lensectomy with vitrectomy of his left eye. To the best of our knowledge, this is the first report of a patient with simultaneous homocystinuria and keratoconus.

【摘要】同型半胱氨酸尿症（homocystinuria）属于先天性代谢缺陷病这一类遗传性疾病范畴，其核心特征为催化同型半胱氨酸转化为胱硫醚的酶活性缺乏。圆锥角膜（keratoconus）是一类以角膜基质变薄、角膜呈锥形为特征的眼科疾病。目前科学文献中关于圆锥角膜与同型半胱氨酸尿症之间关联的研究资料极少。我们认为胶原交联缺陷可能是阐明二者潜在关联的关键机制。本病例报告描述了一名自13岁起确诊为经典型同型半胱氨酸尿症的38岁男性患者：该患者在16岁时因左眼需行晶状体摘除联合玻璃体切除术就诊，最终被确诊为非对称性圆锥角膜。据我们所知，本报告为全球首例同时罹患同型半胱氨酸尿症与圆锥角膜的病例报道。