A pedigree with homocystinuria caused by a novel homozygous CBS gene mutation: A case report.

Homocystinuria, an autosomal recessive metabolic disorder, is caused by cystathionine β-synthase deficiency and presents with diverse clinical manifestations, including ectopia lentis, osteoporosis, scoliosis, premature arteriosclerosis, thromboembolism, and intellectual disability. We present a case in which a pedigree was diagnosed with homocystinuria through comprehensive physical examinations, ophthalmologic evaluations, and genetic testing. Three patients carrying a CBS homozygous mutation with an identical genotype presented with varying degrees of ocular and systemic abnormalities. In this pedigree, homocystinuria remained undiagnosed until the affected individuals sought ophthalmologic care for visual impairment. We identified a novel homozygous missense mutation, c.344G>A, in the CBS gene. This pedigree provides valuable insights into the natural progression and prognosis of homocystinuria in the absence of intervention. Genetic testing plays a critical role in elucidating the etiology of this disorder and differentiating it from other conditions. Thus, it should be considered an essential tool for diagnosis and genetic counseling for patients and their family members. Early detection of metabolic disorders can significantly reduce the risk of severe systemic complications by enabling timely and appropriate therapeutic interventions.