MIDAS syndrome (also known as microphthalmia with linear skin defects [MLS] syndrome) is a rare X-linked dominant neurocutaneous disease primarily affecting females and, much less commonly, XX-genotype males.

Key clinical features include unilateral or bilateral microphthalmia and erythematous or hyperpigmented linear and whorled, slightly depressed plaques on the face and neck that follow Blaschko lines and represent dermal aplasia. Other associated features, though less consistently seen, include sclerocornea, microcephaly, intellectual disability, and congenital cardiac defects (septal defects, cardiomyopathy, arrhythmia).

Prognosis is dependent on the degree of neurologic and cardiac abnormality. The cutaneous lesions present at birth will heal and fade over time.

The syndrome is caused by deletions and mutations affecting the Xp22.2 chromosomal region and the HCCS gene, resulting in defective mitochondrial oxidative phosphorylation and apoptosis.