To describe the anterior segment (AS) findings in patients with microphthalmia with linear skin defects syndrome (MLS), also known as microphthalmia, dermal aplasia, and sclerocornea (MIDAS). A retrospective chart review was conducted to identify patients with a diagnosis of MLS syndrome seen at UPMC Children's Hospital of Pittsburgh. Ophthalmic examination, high-frequency ultrasound, AS optical coherence tomography, and molecular testing were reviewed. Five female patients (10 eyes) were identified. One eye was anophthalmic, one was in a status post penetrating keratoplasty, and eight eyes presented with congenital corneal opacity (CCO). Of these, one showed a normal lens and a very small faint CCO; five showed congenital aphakia and characteristic silvery appearance of the cornea with vascularization; and two showed irido-corneal adhesions in association with normal or abnormal lens and localized avascular CCO. Genetic testing was performed and revealed involvement of HCCS in four patients. In MLS patients, kerato-irido-lenticular dysgenesis can be associated with secondary CCO. It is important to distinguish these CCO from sclerocornea, in order to refine the appropriate management and counseling the parents about the prognosis.

Microphthalmia with linear skin defects (MLS) syndrome is characterized by unilateral or bilateral microphthalmia and/or anophthalmia and linear skin defects, usually involving the face and neck, which are present at birth and heal with age, leaving minimal residual scarring. Other findings can include a wide variety of other ocular abnormalities (e.g., corneal anomalies, orbital cysts, cataracts), central nervous system involvement (e.g., structural anomalies, developmental delay, infantile seizures), cardiac concerns (e.g., hypertrophic or oncocytic cardiomyopathy, atrial or ventricular septal defects, arrhythmias), short stature, diaphragmatic hernia, nail dystrophy, hearing impairment, and genitourinary malformations. Inter- and intrafamilial variability is described. The clinical diagnosis is established when the two major criteria (microphthalmia and/or anophthalmia and linear skin defects) are present and confirmed by identification of a pathogenic variant in COX7B, HCCS, or NDUFB11. However, persons with a molecular diagnosis of MLS syndrome in whom only one of the two major criteria was present have been reported: some show characteristic skin defects without ocular abnormalities and others show eye abnormalities without skin defects. Treatment of manifestations: Use of a prosthesis under the guidance of an oculoplastics specialist for severe microphthalmia and anophthalmia; routine dermatologic care for significant skin lesions; treatment of seizures and/or other neurologic abnormalities by a pediatric neurologist; appropriate developmental therapies and special education as indicated for developmental delay and intellectual disability; routine care for other medical concerns when present. Surveillance: Monitoring and follow up with ophthalmologist, dermatologist, pediatric neurologist, cardiologist, and other professionals as needed. MLS syndrome is inherited in an X-linked manner and is generally lethal in males. Most cases are simplex (i.e., a single occurrence in a family), but rare familial occurrences have been described. Women who are affected or have an MLS syndrome-associated pathogenic variant have a 50% chance of passing the genetic alteration to each offspring. Because male conceptuses with an MLS syndrome-associated pathogenic variant are typically nonviable, the likelihood of a live-born affected child is less than 50%. Molecular genetic testing of at-risk female relatives to determine their genetic status, prenatal testing for a pregnancy at increased risk, and preimplantation genetic testing for MLS syndrome are possible if the disease-causing genetic alteration has been identified in an affected family member.