SNP Shot: Genomic Insights

Burn-McKeown syndrome is a congenital condition, meaning it's present at birth. Individuals with this syndrome exhibit a range of characteristics including nasal passage abnormalities, distinctive facial features, hearing impairment, heart defects, and reduced height.

A common feature of Burn-McKeown syndrome is the narrowing (bilateral choanal stenosis) or complete blockage (bilateral choanal atresia) of both nasal passages. This can lead to severe breathing difficulties in infants, necessitating surgical intervention. Characteristic facial traits include shortened eyelid openings (short palpebral fissures), gaps in the lower eyelids (coloboma), widely spaced eyes (hypertelorism), a prominent nasal bridge, a shortened philtrum (the area between the nose and upper lip), a small mouth opening (microstomia), and large, protruding ears.

Congenital hearing loss affecting both ears is observed in some individuals with Burn-McKeown syndrome, with varying degrees of severity. This hearing loss is classified as mixed, indicating involvement of both the inner ear (sensorineural hearing loss) and the middle ear (conductive hearing loss).

Additional features that may be present in Burn-McKeown syndrome include mild short stature and congenital heart defects, such as patent ductus arteriosus (PDA). PDA involves the persistence of a connection between the aorta and the pulmonary artery, which normally closes shortly after birth. When the ductus arteriosus remains open (patent), infants with PDA may experience rapid breathing, feeding difficulties, and slow weight gain. In severe instances, PDA can lead to heart failure. Notably, cognitive abilities are not affected in Burn-McKeown syndrome.

Inheritance:

Burn-McKeown syndrome follows an autosomal recessive inheritance pattern. This implies that both copies of the responsible gene in each cell must carry mutations for the condition to manifest. The parents of an affected individual each carry one copy of the mutated gene but usually do not exhibit any signs or symptoms of the condition themselves.