Genetics
Both autosomal dominant and recessive forms of Larsen syndrome have been reported. The former is significantly more common than the latter. Symptoms such as syndactyly, cleft palate, short stature, and cardiac defects are seen more commonly in individuals with the autosomal recessive form of the disorder. A lethal form of the disorder has been reported. It is described as being a combination of the Larsen phenotype and pulmonary hypoplasia. Diagnosis
Ultrasound remains as one of the only effective ways of prenatally diagnosing Larsen syndrome. Prenatal diagnosis is extremely important, as it can help families prepare for the arrival of an infant with specifics necessities. Ultrasound can capture prenatal images of multiple joint dislocations, abnormal positioning of legs and knees, depressed nasal bridge, prominent forehead, and club feet. These symptoms are all associated with Larsen syndrome, so they can be used to confirm that a fetus has the disorder. Treatment
Treatment for Larsen syndrome varies according to the symptoms of the individual. Orthopedic surgery can be performed to correct the serious joint defects associated with Larsen syndrome. Reconstructive surgery can be used to treat the facial abnormalities. Cervical kyphosis can be very dangerous to an individual because it can cause the vertebrae to disturb the spinal cord. Posterior cervical arthrodesis has been performed on patients with cervical kyphosis, and the results have been successful  Propranolol has been used to treat some of the cardiac defects associated with Marfans syndrome, so the drug also has been suggested to treat cardiac defects associated with Larsen syndrome.
Sézary disease, or Sézary syndrome, is a type of cutaneous T-cell lymphoma that was first described by Albert Sézary. The affected T cells, known as Sézarys cells or Lutzner cells, have pathological quantities of mucopolysaccharides. Sézary disease is sometimes considered a late stage of mycosis fungoides with lymphadenopathy. Signs and symptoms
Sézary disease and mycosis fungoides are cutaneous T-cell lymphomas having a primary manifestation in the skin. The diseases origin is a peripheral CD4+ T-lymphocyte, although rarer CD8+/CD4- cases have been observed. Epidermotropism (lymphocytes residing in the epidermis)  by neoplastic CD4+ lymphocytes with the formation of Pautriers microabscesses is the hallmark sign of the disease. Although the condition can affect people of all ages, it is commonly diagnosed in adults over age 60. The dominant signs and symptoms of the disease are:

Generalized erythroderma– redness of the skin
Lymphadenopathy – swollen, enlarged lymph nodes
Atypical T cells – malignant lymphocytes known as "Sézary cells" seen in the peripheral blood with typical cerebriform nuclei (brain-shaped, convoluted nuclei)
Hepatosplenomegaly– enlarged liver and spleen
Palmoplantar keratoderma – thickening of the palms of the hands, and soles of the feet

Diagnosis
Those who have Sézary disease often present with skin lesions that do not heal with normal medication. A blood test generally reveals any change in the levels of lymphocytes in the blood, which is often associated with a cutaneous T-cell lymphoma.