Drug therapies for those with cardiac abnormalities, as those abnormalities become severe enough to warrant the use of these therapies. ECGs are mandatory prior to any surgical interventions, due to possible arrythmia. Prognosis
In itself, NSML is not a life-threatening diagnosis, most people diagnosed with the condition live normal lives. Obstructive cardiomyopathy and other pathologic findings involving the cardiovascular system may be a cause of death in those whose cardiac deformities are profound. Epidemiology
Various literature describes the syndrome as being "rare" or "extremely rare". There is no epidemiologic data available regarding how many individuals have the syndrome worldwide; however, there are approximately 200 cases described in medical literature. History
Zeisler and Becker first described a syndrome with multiple lentigines, hypertelorism, pectus carinatum (protruding breastbone) and prognathism (protrusion of lower jaw) in 1936. Sporadic descriptions were added through the years. In 1962, cardiac abnormalities and short stature were first associated with the condition. In 1966, three familial cases were added, a mother, her son and daughter. Another case of mother to two separate children, with different paternity of the two children, was added in 1968.It was believed as late as 2002 that Noonan Syndrome with Multiple Lentigines (NSML) was related to neurofibromatosis type I (von Recklinghausen syndrome). In fact, since both ICD9 and ICD10 lack a specific diagnosis code for NSML, the diagnosis code for NF1 is still sometimes used for diagnostic purposes, although it has been shown that the gene is not linked to the NF1 locus.
Toxicity
Benzoyl peroxide breaks down in contact with skin, producing benzoic acid and oxygen, neither of which is very toxic.The carcinogenic potential of benzoyl peroxide has been investigated. A 1981 study published in the journal Science found that although benzoyl peroxide is not a carcinogen, it does promote cell growth when applied to an initiated tumor. The study concluded, "caution should be recommended in the use of this and other free radical-generating compounds".A 1999 IARC review of carcinogenicity studies found no convincing evidence linking BPO acne medication to skin cancers in humans. However, some animal studies found that the compound could act as a carcinogen and enhance the effect of known carcinogens. Skin irritation
In a 1977 study using a human maximization test, 76% of subjects acquired a contact sensitization to benzoyl peroxide. Formulations of 5% and 10% were used.The U.S. National Institute for Occupational Safety and Health has developed criteria for a recommended standard for occupational exposure to benzoyl peroxide. Cloth staining
Contact with fabrics or hair, such as from still-moist acne medication, can cause permanent color dampening almost immediately. Even secondary contact can cause bleaching, for example, contact with a towel that has been used to wash off benzoyl peroxide-containing hygiene products. Reactivity
The original 1858 synthesis by Liebig reacted benzoyl chloride with barium peroxide, a reaction that probably follows this equation:

2 C6H5C(O)Cl + BaO2 → (C6H5CO)2O2 + BaCl2Benzoyl peroxide is usually prepared by treating hydrogen peroxide with benzoyl chloride under alkaline conditions.