Genetics in Osteoarthritis Knee

*Rajeshwar Nath Srivastava, Amar Chandra Sharma, Sudeepti Ratan Srivastava, Saloni Raj and Lavini Raj*

## **Abstract**

Osteoarthritis (OA) is a debilitating joint disorder with a complex pathogeny wherein diverse factors interact, causing a process of deterioration of the articular cartilage and the subchondral bone. It can be primary or secondary but has common clinical, radiological, and pathological manifestations. Unfortunately, there are no curative or preventive options available for this disease. The knee is the most common site to develop OA among all synovial joints. Both environmental and genetic factors play an essential role in the initiation of the disease. Identifying the genes underlying the genetic background could give new insights into the pathophysiology of knee osteoarthritis (KOA) and could potentially lead to new drug targets. Several genes involving developmental processes or maintenance of cartilage and bone are found to be associated with KOA susceptibility and progression. Understanding the gene functions has improved the knowledge towards the disease pathogenesis. So, it will be of interest to investigate the role of gene-gene interaction in the disease.

**Keywords:** KL grade, knee osteoarthritis, single nucleotide polymorphism, VAS, WOMAC

#### **1. Introduction**

Osteoarthritis (OA) is the most common degenerative arthritis caused by the breakdown of articular cartilage [1]. The prevalence of OA is high and expected to increase in the coming years [2]. Results of some epidemiologic studies indicate that the incidence of symptomatic OA is about 8–9% in China [3]. OA is a multifactorial joint disorder in which growing age, genetic factors; hormonal as well as mechanical factors are significant contributors to its onset and progression. The molecular mechanism underlying the cartilage degeneration is poorly understood [4]. American College of Rheumatology defines Osteoarthritis as a heterogonous group of condition that leads to joint symptoms and signs which are associated with defective integrity of articular cartilage, in addition to related changes in the underlying bone at joint margin [5]. OA is primarily a non-inflammatory disorder of movable joint characterized by an imbalance between the synthesis and degradation of articular cartilage, leading to the classic pathological change of wearing away and destruction of cartilage [6]. OA affects nearly 21 million people in the United States, accounting for 25% of the visits to primary care physicians and half of all having NSAID (Non- Steroid Anti Inflammatory drugs) prescriptions. It is estimated that about 80% of the population was having radiographic evidence of Osteoarthritis by the age of 65 years, although only about 60% of these were

symptomatic [7]. Epidemiological profile of Osteoarthritis in India is not clear, but it is estimated that more than 30-40% of the Indian population suffers from Osteoarthritis over the age of 50 years (www.wrongdiagnosis.com).

Osteoarthritis is considered to be of two types:

1.Primary

2.Secondary
