SNP Shot: Genomic Insights

DOORS syndrome is a rare congenital disorder, meaning it is present at birth. The name "DOORS" is an acronym representing its primary characteristics: deafness, onychodystrophy (abnormal nails), osteodystrophy (short fingers and toes), developmental delay/intellectual disability, and seizures. It's important to note that not every individual with DOORS syndrome exhibits all of these features.

A significant feature in most individuals with DOORS syndrome is severe sensorineural hearing loss, resulting from inner ear abnormalities. Developmental delay and intellectual disability are also frequently pronounced.

Nail abnormalities affect both the hands and feet. The characteristic short fingers and toes stem from hypoplastic terminal phalanges, indicating impaired bone growth at the tips of the digits. In some cases, individuals may possess an extra bone and joint in their thumbs, giving them a triphalangeal appearance resembling other fingers.

Seizures in DOORS syndrome typically manifest during infancy. The most common type is generalized tonic-clonic seizures (grand mal seizures), characterized by muscle rigidity, convulsions, and loss of consciousness. Other seizure types may also occur, including partial seizures (affecting a specific brain area without loss of consciousness), absence seizures (brief loss of consciousness resembling staring spells), and myoclonic seizures (sudden, uncontrolled muscle jerks). In some individuals, seizure frequency and severity increase, leading to potentially life-threatening prolonged seizures known as status epilepticus.

Additional features observed in DOORS syndrome can include microcephaly (unusually small head size) and distinctive facial characteristics, often involving a wide, bulbous nose. Other possible findings include a narrow or high-arched palate, widened alveolar ridges (the parts of the jaw that hold teeth), a shortened frenulum (the membrane connecting the tongue to the floor of the mouth), dental abnormalities, structural heart or urinary tract defects, and hypothyroidism (low thyroid hormone levels). Elevated levels of 2-oxoglutaric acid in urine are also commonly seen, although these levels may fluctuate.

Inheritance:

DOORS syndrome follows an autosomal recessive inheritance pattern. This means that an individual must inherit two copies of the mutated gene (one from each parent) to develop the condition. Parents who each carry one copy of the mutated gene are typically asymptomatic carriers.