Farber lipogranulomatosis and infantile systemic hyalinosis are two rare autosomal recessive diseases with overlapping phenotypic features.Aim
The aim of the study was to present the difficulty in differentiating between these two rare disorders on clinical bases only and emphasize the importance of exome sequencing in the accurate diagnosis of patients with atypical presentations of known genetic diseases.Patients and methods
Two Egyptian cousins born to consanguineous parents presented with hoarseness of cry, painful swollen joint contractures, failure to thrive, diffuse thickening and hyperpigmentation of skin over bony prominences, and death before 2 years of age. Their initial differential diagnosis of Farber disease was ruled out because no pathogenic mutations were identified in the ASAH1 gene in either the proband or the parents. Accurate diagnosis in the affected was revealed as infantile systemic hyalinosis by exome sequencing, showing a homozygous pathogenic variant in the ANTXR2 gene.Conclusion
In the present work we highlight the need for molecular studies by next-generation sequencing for accurate diagnosis, prevention, and proper counseling when genetic diagnosis cannot be reached by other conventional methods.