In people with early-onset severe obesity (defined by an onset before 10 years of age and body mass index over three standard deviations above normal), 7% harbor a single locus mutation. See also
New World Syndrome
Nutritional genomicsRelated:

Human genetic variation


== References ==
Diagnosis
When diagnosing Congenital Erythroipoetic Porphyria (Gunther Disease) one must exclude other forms of porphyria. These include Hepatoerythropoietic Porphyria and rare homozygous variants of Variegate Porphyria, Hereditary Coproporphyria, and STING-associated vasculopathy with onset in Infancy (SAVI). Mild variants may be present similarly to Porphyria Cutanea Tarda.There are four steps in establishing the diagnosis of any porphyria. First, a thorough history (particularly family history) and physical exam are performed with special attention paid to sun-exposed skin. Biochemical measurements of porphyrins and precursors in the urine, feces, and blood are necessary. Specialized labs are helpful in measuring activity of specific enzymes of the heme synthesis pathway and/or DNA and mutational analyses. In CEP, activity of uroporphyrinogen III synthase (the fourth enzyme in the heme biosynthetic pathway) will be markedly decreased.In congenital erythropoietic porphyria, urine aminolavulanic acid and porphobilinogen are typically normal. However, uroporphyrin and coproporphyrin tend to be markedly elevated and moderately elevated, respectively, in the urine more than in the feces. Additionally, fecal protoporphyrin is typically mildly elevated.In the red blood cells, uroporphyrin, coproporphyrin and protoporphyrin are all elevated, distinguishing this form of porphyria from the others. Finally, plasma analysis will demonstrate elevated uroporphyrin and coproporphyrin.Other nonspecific but helpful diagnostic clues are history of cutaneous photosensitivity, blistering, erosions, crusts and ulcerations leading to extensive scarring and deformation of the hands, loss of eyebrows, eyelashes with severe mutilation of cartilaginous structures like the nose, erythrodontia, and variable degree of hematologic involvement ranging from mild hemolytic anemia to intrauterine hydrops fetalis.