In most instances, neurofibromatosis type 1 can be diagnosed clinically according to consensus criteria and genetic testing is only used in atypical presentations or for family planning decisions.Café au lait spots are one of the most characteristic features of neurofibromatosis type 1. They are hyperpigmented lesions of the skin that increase in number and size during the first years of life. They are present in almost all patients but do not have malignant potential. Freckling in the axillary and inguinal regions are another common presenting feature seen in as many as 90% of patients during childhood. Lisch nodules (benign hamartomas of the iris) are seen in almost all patients but they do not cause any visual or ocular impairment. Neurofibromas are benign nerve sheath tumors that occur in peripheral nerves. These typically develop during the teenage years. Neurofibromas do not become malignant but can cause cosmetic concerns as well as local pruritus. When present in the spine they can affect nerve roots and result in both motor and sensory defects. Surgery may be required in some cases. On the contrary, plexiform neurofibromas arise from multiple nerve fascicles and malignant transformation occurs in approximately 10% of cases. They may result in significant morbidity as they may cause organ compression, vascular occlusions, bone destruction, pain and cosmetic issues. Plexiform neurofibromas are seen in 30-50% of patients.Optic pathway gliomas are seen in 15-20% of patients with neurofibromatosis type 1. They most often arise during childhood.
In normal children and adults, insulin secretion should be minimal when blood glucose levels fall below 70 mg/dL (3.9 mM). There are many forms of hyperinsulinemic hypoglycemia caused by various types of insulin excess. Some of those that occur in infants and young children are termed congenital hyperinsulinism. In adults, severe hyperinsulinemic hypoglycemia is often due to an insulinoma, an insulin-secreting tumor of the pancreas.Insulin levels above 3 μU/mL are inappropriate when the glucose level is below 50 mg/dL (2.8 mM), and may indicate hyperinsulinism as the cause of the hypoglycemia. The treatment of this form of hyperinsulinism depends on the cause and the severity of the hyperinsulinism, and may include surgical removal of the source of insulin, or a drug such as diazoxide or octreotide that reduces insulin secretion.That spontaneous hyperinsulinism might be a cause of symptomatic hypoglycemia was first proposed by Seale Harris, MD, 1924, in Journal of the American Medical Association. Dr. Seale Harris first diagnosed hyperinsulinism in 1924  and also is credited with the recognition of spontaneous hypoglycemia. Treatment
See also
Idiopathic hypoglycemia
idiopathic postprandial syndrome

References
External links

GeneReviews/NCBI/NIH/UW entry on Familial Hyperinsulinism