LADD Syndrome
Lacrimo-auriculo-dento-digital (LADD) syndrome is an extremely rare genetic disorder characterized by abnormalities affecting the lacrimal and salivary glands and ducts, ears, teeth and fingers and toes.
Other names of LADD Syndrome
Lacrimo-auriculo-dento-digital syndrome
Levy-Hollister syndrome
Causes of LADD Syndrome
LADD syndrome may occur randomly as the result of a spontaneous genetic change (i.e., new mutation).
The mutation is inherited in an autosomal dominant fashion.
Genetic diseases are determined by the combination of genes for a particular trait that are on the chromosomes received from the father and the mother.
Dominant genetic disorders occur when only a single copy of an abnormal gene is necessary for the appearance of the disease.
The abnormal gene can be inherited from either parent, or can be the result of a new mutation (gene change) in the affected individual.
The risk of passing the abnormal gene from affected parent to offspring is 50% for each pregnancy. The risk is the same for males and females.
Symptoms of LADD Syndrome
Malformations in the network of structures of the eye that secrete tears and drain them from the eyes are often found with LADD syndrome.
These malformations may include an underdeveloped (hypoplastic) or missing (aplastic) opening in the edge of each eyelid that is linked to the tear duct (lacrimal puncta) and/or an obstruction of the channel that carries tears from the tear sac to the nasal opening (nasolacrimal duct).
Absence of the lacrimal puncta is associated with excessive tearing (epiphora), inflammation of the tear sac (dacryocystitis), and keratoconjuntivitis, a condition marked by dryness and inflammation of the cornea and the membrane lining the eyes (conjunctiva).
In some people, underdevelopment or absence of the tear sacs may occur resulting in an absence of tears (alacrima) and dry eyes (xerophthalmia). Less often, an abnormal passage (fistula) from the tear sac to the nasal opening may develop.
Underdevelopment or absence of the salivary glands including the parotid and submandibular glands may occur.
The parotid glands are located in front and below the ears and secrete saliva into the mouth.
The submandibular glands are located underneath the tongue and also secrete saliva into the mouth.
Salivary gland abnormalities may result in dry mouth (xerostomia) and a susceptibility to severe tooth cavities (caries).
Affected individuals may also have small, underdeveloped (hypoplastic) teeth with thin enamel, peg-shaped incisors, and delayed eruption of primary teeth.
Individuals with LADD syndrome may have cup-shaped, low-set ears.
Hearing loss, which has ranged from mild to severe, has also been reported.
Hearing loss may due to blockage of sound waves (conductive), nerve impairment (sensorineural) or both (mixed).
Diagnosis of LADD Syndrome
Molecular genetic testing of the FGF10 gene and selected regions of the FGRF2/3 genes is available to confirm the diagnosis.
Treatment of LADD Syndrome
The treatment of LADD syndrome is directed toward the specific symptoms that are apparent in each individual.
Treatment may require the coordinated efforts of a team of specialists. Pediatricians, surgeons, dental specialists, specialists who assess and treat hearing problems (audiologists), eye specialists and other healthcare professionals may need to systematically and comprehensively plan an affect child’s treatment.
Specific treatment options may include surgery, when appropriate, to relieve the discomfort causing by malfunctioning parts of the lacrimal apparatus or to correct abnormalities of the fingers, toes and forearms.
Hearing aids may benefit some individuals with hearing loss.
Dental care is required on a regular basis.
Artificial tear substitutes may be used to treat dry eyes.
Genetic counseling is recommended for affected individuals and their families.