Question: What is (are) Frontonasal dysplasia ?
Answer: Frontonasal dysplasia is a very rare disorder that is characterized by abnormalities affecting the head and facial (craniofacial) region. Major physical features may include widely spaced eyes (ocular hypertelorism); a flat, broad nose; and a widow's peak hairline. In some cases, the tip of the nose may be missing; in more severe cases, the nose may separate vertically into two parts. In addition, an abnormal skin-covered gap in the front of the head (anterior cranium occultum) may also be present in some cases. Other features may include a cleft lip, other eye abnormalities (coloboma, cataract, microphthalmia), hearing loss, and/or agenesis of the corpus callosum. The majority of affected individuals have normal intelligence. The exact cause of frontonasal dysplasia is not known. Most cases occur randomly, for no apparent reason (sporadically). However, some cases are thought to run in families. Researchers have suggested that this condition is caused by mutations in the ALX3 gene and is inherited in an autosomal recessive fashion.
Source: GARD

Question: What are the symptoms of Frontonasal dysplasia ?
Answer: What are the signs and symptoms of Frontonasal dysplasia? The Human Phenotype Ontology provides the following list of signs and symptoms for Frontonasal dysplasia. If the information is available, the table below includes how often the symptom is seen in people with this condition. You can use the MedlinePlus Medical Dictionary to look up the definitions for these medical terms. Signs and Symptoms Approximate number of patients (when available) Hypertelorism 90% Median cleft lip 50% Midline defect of the nose 50% Aplasia/Hypoplasia of the corpus callosum 7.5% Camptodactyly of finger 7.5% Choanal atresia 7.5% Cleft palate 7.5% Clinodactyly of the 5th finger 7.5% Cognitive impairment 7.5% Conductive hearing impairment 7.5% Craniosynostosis 7.5% Cryptorchidism 7.5% Encephalocele 7.5% Holoprosencephaly 7.5% Hydrocephalus 7.5% Low-set, posteriorly rotated ears 7.5% Preauricular skin tag 7.5% Short stature 7.5% Single transverse palmar crease 7.5% Webbed neck 7.5% The Human Phenotype Ontology (HPO) has collected information on how often a sign or symptom occurs in a condition. Much of this information comes from Orphanet, a European rare disease database. The frequency of a sign or symptom is usually listed as a rough estimate of the percentage of patients who have that feature. The frequency may also be listed as a fraction. The first number of the fraction is how many people had the symptom, and the second number is the total number of people who were examined in one study. For example, a frequency of 25/25 means that in a study of 25 people all patients were found to have that symptom. Because these frequencies are based on a specific study, the fractions may be different if another group of patients are examined. Sometimes, no information on frequency is available. In these cases, the sign or symptom may be rare or common.
Source: GARD