Congenital and hereditary nail disease.

Nail disorders in newborns can show independently or as components of systemic illnesses or genodermatoses. The examination of these abnormalities is complex and sometimes challenging. However, familiarity with these disorders can significantly contribute to uncovering potential underlying conditions. This review includes the physiological nail changes seen within the first few months of life, such as Beau's lines, onychoschizia, koilonychia, congenital nail fold hypertrophy of the first digit, and onychocryptosis. This review also focuses on the most relevant congenital disorders reported and how to perform differential diagnosis. Finally, this review highlights those hereditary diseases in which nail involvement is crucial for diagnosis, such as nail-patella syndrome, congenital pachyonychia, or congenital dyskeratosis, among others.