Fluid collects in the foot when standing and walking and this makes the condition worse. As small muscles lose their nerve supply they can create a cramping feeling. Symptoms
Some of the symptoms are:

Pain and tingling in and around ankles and sometimes the toes
Swelling of the feet and ankle area. Painful burning, tingling, or numb sensations in the lower legs. Pain worsens and spreads after standing for long periods; pain is worse with activity and is relieved by rest. Electric shock sensations
Pain radiating up into the leg, behind the shin, and down into the arch, heel, and toes
Hot and cold sensations in the feet
A feeling as though the feet do not have enough padding
Pain while operating automobiles
Pain along the posterior tibial nerve path
Burning sensation on the bottom of foot that radiates upward reaching the knee
"Pins and needles"-type feeling and increased sensation on the feet
A positive Tinels signTinels sign is a tingling electric shock sensation that occurs when you tap over an affected nerve. The sensation usually travels into the foot but can also travel up the inner leg as well. Causes
It is difficult to determine the exact cause of tarsal tunnel syndrome. It is important to attempt to determine the source of the problem. Treatment and the potential outcome of the treatment may depend on the cause. Anything that creates pressure in the tarsal tunnel can cause TTS. This would include benign tumors or cysts, bone spurs, inflammation of the tendon sheath, nerve ganglions, or swelling from a broken or sprained ankle.
It is also associated with Crigler–Najjar syndrome, a more serious disorder where the enzymes activity is either completely absent (Crigler–Najjar syndrome type I) or less than 10% of normal (type II). Infants may have a developmental deficiency in UDP-glucuronyl transferase, and are unable to hepatically metabolize the antibiotic drug chloramphenicol which requires glucuronidation. This leads to a condition known as gray baby syndrome. Causes
Causes of unconjugated hyperbilirubinemia are divided into three main categories, namely, excessive bilirubin synthesis, liver bilirubin uptake malfunction, and bilirubin conjugation compromise.As to excessive bilirubin synthesis, both intravascular hemolysis and extravascular hemolysis can involve in the pathophysiology. Additionally, dyserythropoiesis and extravasation of blood into tissues such as angioedema and edema can also lead to indirect hyperbilirubinemia, along with heart failure, medication-induced, ethinyl estradiol, chronic hepatitis, and cirrhosis that are, otherwise, attributed to hepatic bilirubin mal-uptake and bilirubin conjugation compromise, respectively. Genes
Human genes which encode UGT enzymes include:

B3GAT1, B3GAT2, B3GAT3
UGT1A1, UGT1A3, UGT1A4, UGT1A5, UGT1A6, UGT1A7, UGT1A8, UGT1A9, UGT1A10
UGT2A1, UGT2A2, UGT2A3, UGT2B4, UGT2B7, UGT2B10, UGT2B11, UGT2B15, UGT2B17, UGT2B28

References
External links
Glucuronosyltransferase at the US National Library of Medicine Medical Subject Headings (MeSH)