In a paper written by Gregory Cochran, Jason Hardy and Henry Harpending of the Department of Anthropology, University of Utah, entitled Natural History of Ashkenazi Intelligence,1 the authors elaborate the hypothesis that the unique demography and sociology of Ashkenazim in medieval Europe selected for (encouraged) intelligence. In the paper, it is said that there are two main clusters of Ashkenazi-inherited disease, the sphingolipid cluster and the DNA repair cluster. Among the other significant Ashkenazi disorders we find idiopathic torsion dystonia and non-classical adrenal hyperplasia which are known to elevate IQ.
In a paper entitled Inborn Errors and Disturbances of Central Neurotransmission (with Special Reference to Phenylketonuria), M. Sandler mentions:
A rather tenuous story of decreased adrenaline and noradrenaline production in the Riley-Day syndrome (familial dysautonomia) is on record (Goodall et al., 1971), despite normal dopamine generation with no impediment in the conversion of dopamine to noradrenaline. It is possible that any change in this disorder is secondary to some distortion of nerve growth factor disposition (Siggers et al., 1976; Schwartz and Breakefield, 1980).2
The paper in which this comment appears is mostly about Phenylketonuria, a genetic disorder that consists mainly of an inability of the body to utilize the essential amino acid, phenylalanine. Classic PKU and the other causes of hyperphenylalaninemia affect mainly Caucasians and Orientals, and to a much lesser extent, Africans. Many of the infants who are born with this condition have blue eyes and fairer hair and skin than other family members. The condition generally leads to severe brain problems such as mental retardation and seizures. So, what is the connection? Riley-Day syndrome. It is found almost exclusively in Ashkenazi Jews. The incidence is estimated to be 1 in 3,700 people, higher than the incidence of PKU.
Infants with this condition have feeding problems and develop pneumonia caused by breathing their formula and food into their airways. Vomiting and sweating spells begin as the infant matures. Young children may also have breath-holding spells that produce unconsciousness, since they can hold their breath for long enough to pass out without feeling the discomfort that normal children would.
A hallmark of Riley-Day syndrome is insensitivity to pain. This leads to unnoticed injuries or injuries that might not have occurred had the child sensed discomfort. Children do not feel the normal sensations that generally warn of impending injury, such as drying of the eyes, pressure over pressure points, and chronic rubbing and chaffing. Bone and skin pain, including burns, are also poorly perceived. However, they can feel visceral pain, like menstrual cramps.
Seizures occur in almost 50% of affected children. They have acute problems with high and low blood pressure. They may have problems regulating their body temperature.3
Riley-Day syndrome is inherited as an autosomal recessive trait, which means that a person must inherit the defective gene from both parents in order to develop the condition.
It is of interest that phenylethylamine possesses very similar pharmacological properties to amphetamine (Mantegazza and Riva, 1963), from which it differs only by the absence of a methyl group on the a-carbon atom. Amphetamine psychosis is almost indistinguishable from paranoid schizophrenia (Janowsky and Risch, 1979) and in accordance with the phenylethylamine hypothesis of schizophrenia (Sandler and Reynolds, 1976), it is not surprising that a high proportion of untreated phenylketonurics manifest with some of the stigmata of the disease which can be attenuated by reduced phenylalanine intake (Blyumina, 1975). These schizophreniform signs may well stem from the prolonged effects of phenylethylamine overproduction.4
Notice that PKU is a disorder that occurs mostly in very Aryan peoples, and Riley Day, a related disorder, only occurs in Ashkenazi. Both disorders seem to have some influence on intelligence. The conclusion is that this disease cluster that Ashkenazi are subjected to is seemingly a price they pay for their higher intelligence. Riley Day seems to be a disorder that embraces some of the known symptoms of psychopathy, a well.
