Anomaly
A deviation from the usual, something different, peculiar, or abnormal.
A congenital anomaly is something that is unusual and different at birth.
A minor anomaly in this context is defined as an unusual anatomic feature that is of no serious medical or cosmetic consequence to the patient.
A minor anomaly of the feet might, for example, be curvature of the second toe so it overlaps the third toe a little.
By contrast, a major anomaly might be a cleft lip and palate, a birth defect of serious medical and cosmetic consequence to the patient.
'Anomaly' comes from the Greek word 'anomalos,' which means 'uneven' or 'irregular.' 'Anomalos' comes from the prefix 'a-' (meaning 'not') and the word 'homalos' (meaning 'even').