Like many other medical conditions, obesity is the result of an interplay between environmental and genetic factors. Studies have identified variants in several genes that may contribute to weight gain and body fat distribution; although, only in a few cases are genes the primary cause of obesity.Polymorphisms in various genes controlling appetite and metabolism predispose to obesity under certain dietary conditions. The percentage of obesity that can be attributed to genetics varies widely, depending on the population examined, from 6% to 85%, with the typical estimate at 50%. It is likely that in each person a number of genes contribute to the likelihood of developing obesity in small part, with each gene increasing or decreasing the odds marginally, and together determining how an individual responds to the environmental factors. As of 2006, more than 41 sites on the human genome have been linked to the development of obesity when a favorable environment is present. Some of these obesogenic or leptogenic genes may influence the obese individuals response to weight loss or weight management. Genes
Although genetic deficiencies are currently considered rare, variations in these genes may predispose to common obesity. Many candidate genes are highly expressed in the central nervous system.Several additional loci have been identified. Also, several quantitative trait loci for BMI have been identified. Confirmed and hypothesized associations include:

Some studies have focused upon inheritance patterns without focusing upon specific genes.
Neonatal hypoglycemia occurs when the neonates blood glucose level is less than the newborns body requirements for factors such as cellular energy and metabolism. There is inconsistency internationally for diagnostic thresholds. In the US, hypoglycemia is when the blood glucose level is below 30 mg/dL within the first 24 hours of life and below 45 mg/dL thereafter. In the UK, however, lower and more variable thresholds are used (<18 mg/dL at any time OR baby with abnormal clinical signs and a single value <45 mg/dL OR baby at risk of impaired metabolic adaptation but without abnormal clinical signs and a measurement <36 mg/dL and remaining <36 mg/dL at next measurement). The neonates gestational age, birth weight, metabolic needs, and wellness state of the newborn has a substantial impact on the neonates blood glucose level. There are known risk factors that can be both maternal and neonatal. This is a treatable condition. Its treatment depends on the cause of the hypoglycemia. Though it is treatable, it can be fatal if gone undetected. Hypoglycemia is the most common metabolic problem in newborns.Neonatal hypoglycemia occurs in between 1 in 3 births out of every 1,000 births but is hard to quantify internationally due to lack of consensus about diagnostic thresholds. It often occurs in premature babies, small full-term babies, babies of diabetic mothers, and is more common in neonatal hypoxic asphyxia, sclerosis, and infected sepsis. Severe hypoglycaemia with persistent or repeated episodes can cause damage to the central nervous system.