SNP Shot: Genomic Insights

Nephronophthisis is a kidney disease marked by inflammation and scarring (fibrosis), which damages kidney function. This damage results in increased urine production (polyuria), excessive thirst (polydipsia), overall weakness, and significant fatigue. Fluid-filled cysts also develop in the kidneys, typically in the corticomedullary region. Furthermore, individuals with nephronophthisis often experience anemia, a deficiency in red blood cells.

Ultimately, nephronophthisis progresses to end-stage renal disease (ESRD), a life-threatening condition where the kidneys can no longer effectively filter fluids and waste from the body. ESRD onset helps classify nephronophthisis: infantile (around age 1), juvenile (around age 13), and adolescent (around age 19).

In approximately 85% of nephronophthisis cases, the condition occurs in isolation, without other associated symptoms. However, some individuals may experience additional features, such as liver fibrosis, heart defects, or situs inversus (a mirror-image reversal of organ placement).

Nephronophthisis can also be a component of broader syndromes known as nephronophthisis-associated ciliopathies, which affect other parts of the body. For instance, Senior-Løken syndrome combines nephronophthisis with retinal degeneration (breakdown of light-sensitive tissue in the eye). Joubert syndrome, affecting numerous body systems, can cause neurological issues and other features, including nephronophthisis.

Inheritance:

Nephronophthisis follows an autosomal recessive inheritance pattern. This means that both copies of the responsible gene in each cell must have mutations for the condition to manifest. Individuals with one mutated copy of the gene are carriers and usually don't exhibit symptoms, but both parents must be carriers to have an affected child.