The following terminology is frequently used by health care professionals in the discussion of Treacher Collins syndrome. Each term is defined in language that the non-professional can understand. If a definition contains a word with which you are not familiar, refer to that word.

anomaly
absence, deformity, or excess of body parts as the result of faulty development of the embryo

antimongoloid slant of eyes
downward slant of eyes

apnea
no breathing

atresia of the ear canals
absence or closure of the ear canals

auricle
outer ear

autosomal dominant
A form of gene inheritance. Two genes are received, one from the mother and one from the father. A single copy of the syndrome gene (received from either the mother or the father) will be expressed "dominating" the other normal gene and resulting in the appearance of the syndrome. With each conception, a 50% chance exists that the affected parent will transmit the gene to the child.

bilateral
affecting both sides

CAT scan
computerized axial tomography; seeCT scan

choana
back part of the nasal passage

choanal atresia
lack of an open nasal air passage

cleft
a fissure or longitudinal opening

cleft lip
congenital (at birth) opening in the lip

cleft palate
congenital (at birth) opening in the roof of the mouth

coloboma
cleft of the lower eyelid

conductive hearing aid
hearing aid used for a conductive hearing loss

conductive hearing loss
impaired transmission of sound waves through the external ear canal to the bones of the middle ear

congenital
present at and existing from the time of birth

CT scan
radiologic imaging technique that produces images of "slices" 1 cm thick through the patient's body

dysmorphology
science of studying abnormal forms

dysostosis
abnormality of bone

ear canal
canal which connects the external ear to the middle ear

expression
manifestation of a heritable trait in an individual carrying the gene(s) that determine it

expressivity
extent to which a heritable trait is manifested by an individual carrying the principal gene(s) that determine it

fissure
narrow clit or cleft

fistula
tubelike passage between body tissue, usually between two internal organs or leading from an internal organ to the body surface

Francheshetti-Klein syndrome
another name for Treacher Collins syndrome

Francheshetti's syndrome
another name for Treacher Collins syndrome

gastrostomy
incision into the stomach

gastrostomy tube (g-tube)
feeing tube used in gavage

gavage
when feeding is passed through a tube in the stomach

hard palate
boney part of the palate behind which one finds the soft palate where there is no bone present

hypoplasia
incomplete development or underdevelopment of an organ or tissue, often used with zygomatic arches and teeth

incompetent
not able to function properly

lateral canthal dystopia
abnormal location of the outer part of the eyelids where they come together

macrostomia
excessive width of the mouth

malar
cheek

malar hypoplasia
incompetent development or underdevelopment of the cheek or cheekbone

malocclusion
malposition of the teeth resulting in faulty meeting of the teeth or jaws

mandible
lower jaw; there is also an upper jaw

Mandibulofacial Dysostosis
another name for Treacher Collins syndrome

mastoid
projection at the base of the temporal bone

maxilla
one of two identical bones which form the upper jaw

micrognathia
abnormal smallness of the jaws, especially the lower jaw

microcephaly
small size of the head in relation to the rest of the body

microsomia
abnormally small size of the body

microtia
smallness of the outer ear

morphologic
form and structure of a particular organism, organ, tissue or cell

naso
prefix for nose

nasogastric tube (ng tube)
soft tube that is inserted through a nostril and into the stomach for the purpose of instilling liquid foods or other substances

ossicle
a small bone, especially of those of the middle ear

ossification
formation into bone or boney substance

palpebral
eyelid

palpebral fissures
normal space between the upper and lower eyelids

palate
roof of the mouth

penetrance
frequency with which a heritable trait is manifested by individuals carrying the principal gene(s) conditioning it

preauricular
in front of the auricle or outer ear

preauricular ear tags
small appendages in front of the flap of the outer ear

sleep apnea
episodes when breathing stops during sleep

soft palate
fleshy part arching downward from the hard palate to the throat

spontaneous mutation
change in the genetic material at the time of conception

stenosis
narrowing of a body passage or opening

syndrome
combination of symptoms resulting from a single cause

tag
small appendage or flap

temporal bone
contains the organs of hearing ; located on the side of head, above the ears

trachea
windpipe

tracheostomy (trach)
creation of an opeing into the trachea through the neck, with insertion of a tube to facilitate passage of air or evacuation of secreations

Treacher Collins
name of the English opthamologist who first described this syndrome in the medical literature in 1900

Treacher Collins syndrome
is a rare genetic condition characterized by underdevelopment of the cheeks, the lower jaw and jaw bone, downwardly slanting eyes, and a receding chin. The outer ear(s) may be malformed along with the ear canals. It is inherited as an autosomal dominant trait. 60% of cases mutation.

Treacher Collins - Francheschetti syndrome
another name for Treacher Colloins syndrome

unilateral
affecting only one side

variability of expression
expression (of gene) varies relative to characteristics and degree affected

zygoma
same as the malar bone

zygomatic arches
arch formed by the projection of the zygoma and temporal bones<

According to the database of the National Organization for Rare Disorders (NORD) the following rare conditions have characteristics similar to those of Treacher Collins syndrome (TCS). Comparisons may be useful for a differential diagnosis:

• Nager Acrofacial Dysostosis,
• Goldenhar-Gorlin syndrome,
• Oral-Facial-Digital syndrome, and
• Juber-Hayward syndrome (Orocraniodigital syndrome.)

Pierre Robin Sequence and Miller syndrome are rare disorders with characteristics similar to those of Treacher Collins syndrome. In some situations it is difficult to tell the difference between a bilateral form of Hemifacial Microsomia, which is a quite common congenital condition. If there is bilateral facial microsomia, the condition may appear much the same as TCS. A three dimension CAT scan sometimes gives information that can be used to separate between the two conditions, based on the absence of the zygomatic arch.