SNP Shot: Genomic Insights

Miller syndrome is an uncommon disorder primarily impacting the development of the face and limbs, with the degree of severity differing from person to person.

Infants with Miller syndrome are typically born with underdeveloped cheekbones (malar hypoplasia) and a noticeably small lower jaw (micrognathia). Cleft palate and/or cleft lip are also common. These facial differences often lead to difficulties with feeding in infancy. Furthermore, the small lower jaw can constrict the airway, potentially resulting in dangerous breathing complications.

Characteristics of Miller syndrome often include downward-slanting eyes, ectropion (where the eyelids turn outward), and coloboma (a notch) in the lower eyelids. Many individuals have small, cup-shaped ears, and some experience conductive hearing loss due to middle ear defects. The presence of extra nipples is another possible feature. While intelligence is not affected by Miller syndrome, speech development may be delayed because of hearing impairments.

People with Miller syndrome exhibit a range of bone abnormalities in their arms and legs. A frequent finding is the absence of the fifth fingers (pinkies) and toes. Syndactyly (webbed or fused fingers or toes) and abnormally shaped bones in the forearms and lower legs are also possible. Occasionally, bone defects may occur in other areas, such as the ribs or spine.

Less frequently, individuals with Miller syndrome may have abnormalities affecting the heart, kidneys, genitalia, or gastrointestinal system.

Inheritance:

Miller syndrome follows an autosomal recessive inheritance pattern. This means that both copies of the responsible gene in each cell must have a mutation for the condition to develop. Individuals with Miller syndrome inherit one mutated copy from each parent, who are typically carriers of the gene mutation but do not exhibit symptoms of the condition themselves.