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Deafness with labyrinthine aplasia microtia and microdontia (LAMM)

MedGen UID:
342803
Concept ID:
C1853144
Disease or Syndrome
Synonyms: Congenital Deafness with Inner Ear Agenesis, Microtia, and Microdontia; DEAFNESS, CONGENITAL, WITH LABYRINTHINE APLASIA, MICROTIA, AND MICRODONTIA
Modes of inheritance:
Autosomal recessive inheritance
MedGen UID:
141025
Concept ID:
C0441748
Intellectual Product
Sources: HPO, OMIM, Orphanet
A mode of inheritance that is observed for traits related to a gene encoded on one of the autosomes (i.e., the human chromosomes 1-22) in which a trait manifests in homozygotes. In the context of medical genetics, autosomal recessive disorders manifest in homozygotes (with two copies of the mutant allele) or compound heterozygotes (whereby each copy of a gene has a distinct mutant allele).
Autosomal recessive inheritance (HPO, OMIM, Orphanet)
SNOMED CT: Congenital deafness with inner ear agenesis, microtia, and microdontia (702360007); LAMM syndrome (702360007); Congenital deafness with labyrinthine aplasia, microtia and microdontia (702360007)
 
Gene (location): FGF3 (11q13.3)
OMIM®: 610706

Disease characteristics

Congenital deafness with labyrinthine aplasia, microtia, and microdontia (LAMM syndrome) is characterized by: profound bilateral congenital sensorineural deafness associated with inner ear anomalies (most often bilateral complete labyrinthine aplasia); microtia (type I) that is typically bilateral (although unilateral microtia and normal external ears are observed on occasion); and microdontia (small teeth). Individuals with LAMM syndrome commonly have motor delays during infancy presumably due to impaired balance from inner ear (vestibular) abnormalities. Growth, physical development, and cognition are normal.  [from GeneReviews]
Authors:
Jessica Ordonez  |  Mustafa Tekin   view full author information

Additional description

From GHR
Congenital deafness with labyrinthine aplasia, microtia, and microdontia (also called LAMM syndrome) is a condition that affects development of the ears and teeth. In people with this condition, the structures that form the inner ear are usually completely absent (labyrinthine aplasia). Rarely, affected individuals have some underdeveloped inner ear structures in one or both ears. The abnormalities of the inner ear cause a form of hearing loss called sensorineural deafness that is present from birth (congenital). Because the inner ear is important for balance as well as hearing, development of motor skills, such as sitting and crawling, may be delayed in affected infants. In addition, people with LAMM syndrome often have abnormally small outer ears (microtia) with narrow ear canals. They can also have unusually small, widely spaced teeth (microdontia).  https://ghr.nlm.nih.gov/condition/congenital-deafness-with-labyrinthine-aplasia-microtia-and-microdontia

Clinical features

Anteverted ears
MedGen UID:
384047
Concept ID:
C1857055
Finding
Aplasia of the inner ear
MedGen UID:
382376
Concept ID:
C2674502
Absence of the inner ear due to a developmental defect.
Microtia, first degree
MedGen UID:
866821
Concept ID:
C4021175
Anatomical Abnormality
Presence of all the normal ear components and the median longitudinal length more than two standard deviations below the mean.
Profound sensorineural hearing impairment
MedGen UID:
868926
Concept ID:
C4023338
Disease or Syndrome
Complete loss of hearing related to a sensorineural defect.
Delayed gross motor development
MedGen UID:
332508
Concept ID:
C1837658
Finding
A type of motor delay characterized by an delay in acquiring the ability to control the large muscles of the body for walking, running, sitting, and crawling.
Micrognathia
MedGen UID:
44428
Concept ID:
C0025990
Congenital Abnormality
Developmental hypoplasia of the mandible.
Micrognathia
MedGen UID:
44428
Concept ID:
C0025990
Congenital Abnormality
Developmental hypoplasia of the mandible.
Microdontia
MedGen UID:
66008
Concept ID:
C0240340
Congenital Abnormality
Decreased size of the teeth, which can be defined as a mesiodistal tooth diameter (width) more than 2 SD below mean. Alternatively, an apparently decreased maximum width of tooth.
Long face
MedGen UID:
324419
Concept ID:
C1836047
Finding
Facial height (length) is more than 2 standard deviations above the mean (objective); or, an apparent increase in the height (length) of the face (subjective).
Widely spaced teeth
MedGen UID:
337093
Concept ID:
C1844813
Finding
Increased spaces (diastemata) between most of the teeth in the same dental arch.
Conical tooth
MedGen UID:
860796
Concept ID:
C4012359
Finding
An abnormal conical form of the teeth, that is, a tooth whose sides converge or taper together incisally.
Skin tags
MedGen UID:
11452
Concept ID:
C0037293
Neoplastic Process
Cutaneous skin tags also known as acrochorda or fibroepithelial polyps are small benign tumours that may either form secondarily over time primarily in areas where the skin forms creases, such as the neck, armpit or groin or may also be present at birth, in which case they usually occur in the periauricular region.

Recent clinical studies

Therapy

Dill P, Schneider J, Weber P, Trachsel D, Tekin M, Jakobs C, Thöny B, Blau N
Mol Genet Metab 2011 Nov;104(3):362-8. Epub 2011 Jun 2 doi: 10.1016/j.ymgme.2011.05.019. PMID: 21752681

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