It is perfectly normal for the lunula to be visibly missing from a person's fingernails, as not everyone has visible lunulae, according to Wikipedia. For some people, the eponychium, a thickened layer of skin, covers the lunula so it is not visible.
The lunula is the pale, crescent moon-shaped area typically seen under the nail at the base of the fingernails; it is usually most visible on the thumbnail. Although protected by the nail, the lunula is delicate. If it becomes damaged, the entire nail becomes deformed as a result. One problem with the lunula is spotted lunula, which occurs when the capillaries under the area become congested, resulting in the lunula become red, notes WebMD.