The other with hypotelorism (a decreased distance between the eyes), this includes holoprosencephaly (failure of development of the forebrain). In addition, a craniofacial cleft can be classified using the Tessier classification. Each of the clefts is numbered from 0 to 14. The 15 different types of clefts are then subdivided into 4 groups, based on their anatomical position in the face: midline clefts, paramedian clefts, orbital clefts and lateral clefts. FND is a midline cleft, classified as Tessier 0/14. Besides this, the additional anomalies seen in FND can be subdivided by region. None of these anomalies are specific for the syndrome of FND, but they do occur more often in patients with FND than in the population. The anomalies that may be present are:

Nasal: mild anomalies to nostrils that are far apart and a broad nasal root, a notch or cleft of the nose and accessory nasal tags. Ocular: narrowed eye slits, almond shaped eyes, epicanthal folds (extra eyelid tissue), epibulbar dermoids (benign tumors of the eye), upper eyelid colombas (full thickness upper eyelid defects), microphthalmos (one or two small eyes), congenital cataract and degeneration of the eye with retinal detachment. Facial: telecanthus (an increased distance between the corners of the eye), a median cleft of the upper lip and/or palatum, and a V-shaped hairline.
Organs develop out of primordia (tissue in its earliest recognizable stage of development). The developmental processes of the face and jaw structures originate from different primordia:

Unpaired frontonasal process
Paired nasomedial and nasolateral processes
Paired maxillary processes and mandibular processes

The formation of the frontonasal process is the result of a complex signaling system which begins with the synthesis of retinoic acid (a vitamin A metabolite). This is needed to set up the facial ectodermal zone. This zone makes signaling molecules that stimulate the cell proliferation of the frontonasal process. A midfacial defect will occur if this signaling pathway is disrupted. It is suggested that the absence of this pathway will lead to the formation of a gap, and that when the pathway is working too hard, excessive tissue will be formed. FND consists of various nasal malformations that result from excessive tissue in the frontonasal process, which results in hypertelorism and a broad nasal bridge.Between the 4th and 8th week of pregnancy, the nasomedial and maxillary processes will fuse to form the upper lip and jaw. A failure of the fusion between the maxillary and nasomedial processes results in a cleft lip. A median cleft lip is the result of a failed fusion between the two nasomedial processes. The palate is formed between the 6th and 10th week of pregnancy. The primordia of the palate are the lateral palatine processes and median palatine processes. A failure of the fusion between the median and lateral palatine processes results in a cleft palate.