SNP Shot: Genomic Insights

Bartter syndrome encompasses a set of closely related kidney conditions that disrupt the balance of electrolytes like potassium, sodium, and chloride within the body.

Sometimes, signs of Bartter syndrome are present even before a baby is born. It can lead to polyhydramnios, a condition characterized by an excessive amount of amniotic fluid around the developing fetus. This increases the likelihood of premature delivery.

Starting in infancy, individuals with Bartter syndrome often experience difficulties in growing and gaining weight appropriately (failure to thrive). They excrete excessive amounts of salt (sodium chloride) in their urine, leading to dehydration, constipation, and increased urination (polyuria). Furthermore, they lose significant amounts of calcium through their urine (hypercalciuria), which can weaken the bones (osteopenia). This excess calcium can also deposit in the kidneys during urine concentration, causing hardening of the kidney tissue (nephrocalcinosis). Low potassium levels in the blood (hypokalemia) are another hallmark of Bartter syndrome, potentially causing muscle weakness, cramps, and fatigue. In rare cases, children with Bartter syndrome may develop hearing loss due to inner ear abnormalities (sensorineural deafness).

Bartter syndrome is broadly categorized into two main forms based on when symptoms appear and how severe they are. One form, known as antenatal Bartter syndrome, begins before birth and is often very serious. The other form, often referred to as classical Bartter syndrome, starts in early childhood and is generally milder. With the identification of the genetic causes of Bartter syndrome, it has also been classified into different types based on the specific gene involved. Types I, II, and IV are characterized by the features of antenatal Bartter syndrome. Type IV, because it includes hearing loss, is also known as antenatal Bartter syndrome with sensorineural deafness. Type III typically presents with the characteristics of classical Bartter syndrome.

Inheritance:

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