 At any age, children may develop an abnormal sensitivity to light photophobia and irritation due to the formation of cystine crystals in the cornea. The severity of photophobia can vary.Affected children may also develop deficiency of thyroid hormone production hypothyroidism due to cystine crystals accumulating in the thyroid. The thyroid is a butterfly shaped gland located at the base of the neck. The thyroid secretes hormones into the bloodstream that influence certain activities of the body such as growth, maturation and the rate of metabolism. Symptoms of hypothyroidism are highly variable, but may include fatigue, feeling cold, dry skin, constipation and depression. Children with nephropathic cystinosis do not produce tears, sweat or salivate normally. Tear production may be diminished causing the eyes to dry out. An impaired ability to sweat can potentially cause total exhaustion or collapse due to heat heat prostration. The increased longevity of individuals with nephropathic cystinosis has revealed that additional complications affecting organs other than the kidneys can occur later during life. These complications develop due to the chronic accumulation of cystine crystals in individuals who have not been adequately treated by cysteamine, although they have undergone a kidney transplant. These additional complications generally develop between 20 and 40 years of age. Accumulation of cystine in muscle tissue can cause muscle disease myopathy leading to progressive weakness and wasting of affected muscles. Impairment of muscles in the throat can lead to swallowing and feeding difficulties. Involvement of chest muscles can result in pulmonary insufficiency.A wide variety of gastrointestinal symptoms can develop including enlargement of the liver hepatomegaly causing high blood pressure of the main vein of the liver portal hypertension, enlargement of the spleen splenomegaly, gastroesophageal reflux, ulcers, inflammation of the esophagus esophagitis, and dysfunction of the muscles of the gastrointestinal tract dysmotility. Additional symptoms include inflammatory bowel disease, tearing of the bowel causing the contents of the intestines to flow into the abdominal cavity bowel perforation, and inflammation of the peritoneum peritonitis, which is the membrane that lines the abdominal wall and organs. 