Second 46,XX male with MLS syndrome

Area of Science:

• Genetics
• Developmental Biology
• Clinical Medicine

Background:

• Microphthalmia with Linear Skin Defects (MLS) syndrome is a rare genetic disorder.
• 46,XX male individuals represent a specific subset of sex chromosome variations.
• Understanding the genetic basis of MLS syndrome is crucial for diagnosis and management.

Observation:

• A second case of a 46,XX male diagnosed with MLS syndrome is presented.
• The patient exhibited microphthalmia, linear skin defects, secundum atrial septal defect, hypospadias with chordee, anal fistula, and agenesis of the corpus callosum with colpocephaly.
• Histopathological examination of skin lesions revealed smooth muscle hamartomata, differing from previous assumptions of dermal aplasia.

Findings:

• Genetic analysis confirmed a deletion in one X chromosome and the presence of a derivative X chromosome resulting from an X;Y translocation in the patient.
• Ophthalmologic evaluation excluded retinal lacunae, distinguishing the case from Aicardi syndrome.
• The combination of MLS syndrome features with a derivative X chromosome from X;Y translocation provides new insights into the genetic etiology.

Implications:

• This case expands the known phenotypic spectrum associated with 46,XX males and MLS syndrome.
• The findings highlight the importance of comprehensive genetic testing, including FISH studies, for diagnosing complex congenital anomalies.
• Further research into X;Y translocations and their role in developmental disorders is warranted.