When They Mutate by Dr. Apurva Mishra & Prof. R. K. Pandey - HTML preview

96) Peutz-Jeghers Syndrome :

(Hereditary intestinal polyposis, Intestinal polyposis with melanin pigmentation)

The condition is inherited as an autosomal dominant trait. A gene was found to be associated with the mutation. On chromosome 19, the gene known as STK11 ( LKB1) is a possible tumor suppressor gene.

Clinical features :

a) Skin :

There are numerous, usually discrete, brown to bluish black macules on skin, especially about the facial orifices—perioral, perinasal and periorbital. The macules range from 1 to 5 mm in diameter. The pigmentation is usually present from birth and seems to fade somewhat at about puberty.

b) Oral manifestations :

Round, oval or irregular, rarely, confluent macules of bluish-gray pigment of variable intensity may be seen on the lips (especially lower lip) and oral mucosa. These are somewhat larger than those on skin, about 1 to 12 mm in size.

They also involve buccal mucosa and less frequently palate, gingiva and floor of the mouth. The facial pigment tends to fade later in life, but the mucosal pigmentation persists.

97) Pierre Robin Syndrome :

Etiology :

It is thought to be caused by the malposition and interposition of the tongue between the palatal shelves. Arrest of mandibular development may prevent descent of the tongue and failure of palatal shelf elevation and fusion. Recent evidences suggest that the primary defect may be due to genetically infl uenced metabolic growth disturbances of the maxilla and mandible rather than to mechanical obstruction by the tongue, during embryogenesis.

Clinical features:

a) Oral manifestations :

• Oral changes are the most evident ones in this syndrome. It consists of micrognathia, cleft palate, and glossoptosis.
• In this syndrome, the primary defect is hypoplasia of the mandible which prevents the normal descent of the developing tongue between the medially growing palatal shelves resulting in cleft palate. Because of this mechanism cleft lip does not occur in association with cleft palate.
• The hypoplastic mandible, characteristically produces ‘bird facies’.
• The most important result of this jaw malformation is respiratory and feeding difficulties, although exact explanation of its occurrence is uncertain.
• The usual suggestion is that failure of support of tongue musculature occurs because of the micrognathia, allowing the tongue to fall down and backward, partially obstructing epiglottis.
• Feeding problems are thought to be due to inadequate control of the tongue. Usually these patients have difficulty during the inspiratory phase of respiration with periodic cyanotic attacks. The tongue acts as a ball valve preventing inhalation but allowing exhalation.

b) Face :

It is typically described as ‘Birds facies’ or ‘Andy Gump’ appearance. About 20% of the patients are mentally retarded. There can also be congenital heart defects like patent ductus arteriosus and foramen ovale: auricular septal defect and coarctation of aorta.