Norum disease

Norum Disease: A Rare Genetic Disorder

Norum disease, also known as complete LCAT deficiency, is a rare genetic disorder that primarily affects the eyes and kidneys. The condition is characterized by a gradual clouding of the clear front surface of the eyes (the corneas), which generally first appears in early childhood [3]. This cloudiness can lead to vision problems and other eye-related issues.

In addition to eye problems, Norum disease also affects the kidneys, causing proteinuria (excess protein in the urine) and renal failure [4], [8], [14]. The condition is caused by a deficiency of the enzyme lecithin:cholesterol acyltransferase (LCAT), which impairs the breakdown of lipoproteins, leading to their accumulation and damage to tissues [5].

The symptoms of Norum disease may start to appear at any time in life, but they can also begin in early childhood [13]. The condition is inherited in an autosomal recessive manner, meaning that a person must inherit two copies of the mutated gene (one from each parent) to develop the disease [15].

Key Features:

• Clouding of the corneas
• Proteinuria and renal failure
• Deficiency of LCAT enzyme
• Autosomal recessive inheritance pattern

References:

[3] Description of complete LCAT deficiency. [4] Norum disease Summary. [5] A form of lecithin-cholesterol acyltransferase deficiency (LCAT) characterized clinically by corneal opacities, hemolytic anemia, ... [8] The mutation leading to Norum disease causes normocytic hemolytic anemia with significant proteinuria secondary to renal failure. [14] The mutation leading to Norum disease causes normocytic hemolytic anemia with significant proteinuria secondary to renal failure. [15] Norum disease is an autosomal recessive inherited disorder of lipoprotein which results from a deficiency of alpha lecithin-cholesterol acyltransferase.

Norum Disease Signs and Symptoms

Norum disease, also known as complete LCAT deficiency, is a rare genetic disorder that primarily affects the eyes and kidneys. The signs and symptoms of this disease can vary in severity and age of onset.

• Corneal opacities: These are cloudy areas on the cornea, which can cause severe vision loss [4].
• Hemolytic anemia: This is a condition where red blood cells are broken down, leading to pale complexion and fatigue [3].
• Kidney disease: Individuals with Norum disease often experience progressive renal failure, which can lead to kidney failure over time [1].
• Vision impairment: The cloudy corneas can cause significant vision problems, including blindness in severe cases [5].
• Early atherosclerosis: This is a condition where the arteries become hardened and narrowed, leading to cardiovascular problems [3].
• Other symptoms: These may include anemia due to destruction of red blood cells, hypertriglyceridemia, protein in urine, and blood in the urine [3].

It's essential to note that the age of onset for these symptoms can vary significantly among individuals with Norum disease. Some people may experience symptoms in early childhood, while others may not develop them until later in life.

References:

[1] Complete LCAT deficiency often has kidney disease that begins in adolescence or early adulthood. [3] Symptoms of this disease may start to appear at any time in life. [4] Corneal opacities usually develop in early childhood and are characterized by grayish dots throughout the corneal stroma. [5] What are the signs and symptoms? · Cholesterol build-up on the corneas making them cloudy and causing severe loss of vision

Diagnostic Tests for Norum Disease

Norum disease, also known as Lecithin-Cholesterol Acyltransferase (LCAT) deficiency, can be diagnosed through a combination of clinical evaluation, laboratory tests, and genetic testing.

• Blood Tests: Blood tests can reveal elevated liver enzymes and abnormal cholesterol levels, which may indicate the presence of the disease [11].
• Specialized Blood Test: A specialized blood test is used to diagnose LCAT deficiency [5].
• Kidney Biopsy: A kidney biopsy may be required to confirm the diagnosis, as it can show distinctive lipid deposits in the glomeruli on histology [1].
• Genetic Testing: Genetic testing can detect mutations in the LCAT gene, which results in a deficiency or dysfunction of the LCAT enzyme [14]. This test provides a comprehensive analysis of genes associated with inherited lipidemias [8].
• Next-Generation Sequencing: Next-generation sequencing is used to detect single nucleotide and copy number variants in 13 genes associated with primary hypertriglyceridemia, including the LCAT gene [9].

Additional Tests

Other laboratory tests may be performed to support the diagnosis of Norum disease, including:

• Complete blood count (CBC)
• Urinalysis
• Blood chemistries
• Lipid panels
• Plasma LCAT activity test

It's essential to note that a combination of these tests and clinical evaluation is necessary for an accurate diagnosis. A team of providers with advanced medical training in different body systems or types of diseases can provide diagnostic procedures in their area of expertise [12].

Current Status of Drug Treatment for Norum Disease

Unfortunately, there are currently no treatment options available to alter the course of LCAT deficiency, also known as Norum disease [4]. The condition primarily affects the eyes and kidneys, leading to corneal opacities, hemolytic anemia, and renal failure [3].

Research and Development

However, researchers are actively exploring potential treatments for Norum disease. One approach is enzyme replacement therapy (ERT), which involves replacing the deficient LCAT enzyme with a functional one [6]. Another potential treatment option is gene therapy, which aims to correct the genetic mutation responsible for the condition [7].

Clinical Trials and Compassionate Use

Several clinical trials are underway or have been completed to evaluate the safety and efficacy of various treatments for Norum disease. For example, ABIONYX Pharma has provided CER-001 under named compassionate use to eight patients with LCAT Deficiency in 4 European countries [8]. Additionally, researchers are investigating the potential of HDL vectors as a treatment option [5].

Challenges and Future Directions

Despite these research efforts, treating Norum disease remains a significant medical challenge. The condition's complex pathophysiology and limited understanding of its underlying mechanisms hinder the development of effective treatments. However, ongoing research and clinical trials offer hope for improving the lives of individuals affected by this rare disorder.

References:

[3] Complete LCAT deficiency is a disorder that primarily affects the eyes and kidneys. [4] There are currently no treatment options to alter the course of LCAT deficiency, known as Norum disease after the Norwegian physician Kaare ... [5] ○ Treatment of LCAT deficiency or Norum disease presents a major medical challenge, given the ... of renal and ophthalmological diseases, or new HDL vectors used ... [6] by KR Norum · 2020 · Cited by 35 — The two main potential indications for rhLCAT would be for the treatment of FLD and for raising HDL-cholesterol for the possible treatment of cardiovascular ... [7] by M Kuroda · 2021 · Cited by 12

Differential Diagnosis of Norum Disease

Norum disease, also known as Familial Lecithin-Cholesterol Acyltransferase (FLCAT) deficiency, is a rare genetic disorder that affects the body's ability to break down certain fats (lipids). When diagnosing Norum disease, it is essential to consider differential diagnoses to rule out other conditions with similar symptoms.

Conditions to Consider:

• Fish-eye disease (FED): A partial deficiency in LCAT activity, which can present with similar symptoms to Norum disease.
• Hemolytic anemia: A condition characterized by the breakdown of red blood cells, which is often associated with Norum disease.
• Corneal opacities: A condition where the cornea becomes cloudy or opaque, which is a common symptom of Norum disease.
• Xanthoma: A condition characterized by the accumulation of fatty deposits in the skin and other tissues.

Diagnostic Criteria:

To diagnose Norum disease, healthcare professionals consider the following criteria:

• Family history of characteristic disease features
• Clinical signs such as corneal opacities, hemolytic anemia, and xanthoma
• Laboratory tests showing a severe reduction of plasma HDL cholesterol

Key Points to Consider:

• Genetic testing: Genetic testing can confirm the presence of mutations in the LCAT gene, which is responsible for Norum disease.
• Imaging studies: Imaging studies such as echocardiography and ultrasound can help identify characteristic features of Norum disease.

According to [1], differential diagnosis includes fish-eye disease (FED) sharing common biochemical features. This case, added to the reduced number of publications on this topic, underlines the need for a timely differential diagnosis aiming to address patients to preventive programs and future available therapies [3].

References:

[1] Context result 3 [2] Context result 5 [3] Context result 6