Nature, Nurture, and Nyhan's Syndrome

Nature, Nurture, and Nyhan’s Syndrome

Kate Gould

One of my friends recently asked me what I thought of the “Nature versus Nurture” debate. Her opinion was that, no matter the genetic components, behavior could be “rewritten” by education and parenting during one’s childhood. Did I think that “Nature,” biology and genetics, had more of a role in determining human behavior than “Nurture,” environmental influences, such as parenting, might? In order to answer her question, I had to relate an article I recently read, about an unusual syndrome that might shed some light on her question. Lesch-Nyhan syndrome, sometimes called Nyhan’s syndrome or Kelley-Seegmiller syndrome, could change her view about Nature versus Nurture.

            Lesch-Nyhan is an X-linked recessive disease affecting almost entirely male children, although there are a few, very rare female cases. It is passed from mother to son, most often, although one-third of all cases arise from new mutations. Lesch-Nyhan is characterized by the overproduction and accumulation of uric acid, a waste product of chemical processes in blood and urine. Uric acid accumulates in the joints, causing gouty arthritis, and can cause kidney and bladder stones (1). But the most notable problem associated with Lesch-Nyhan is not from a metabolic disorder—it’s a behavioral one. Self-injury, from biting to head banging to scratching and gouging, is uncontrollable.

Persons affected by LNS compulsively hurt themselves, often biting off their lips and their fingers, requiring that their hands be bound and their upper front teeth removed. And they don’t want to. They are well aware of a sudden impulse to harm themselves—young boys, often mentally impaired (another symptom of LNS), scream in horror as their hands inch toward their faces, ripping at their eyes and their cheeks. They feel the same pain that you and I do, but they are unable to control their impulse towards self-injury. And the self-injuring behavior associated with LNS is not limited to physical harm—people affected by Lesch-Nyhan are often compelled to scream and rage at people they like, to answer test questions wrong despite a desire to succeed, to say “No” when they mean “Yes…” The dark thoughts that we all have floating at the back of our minds, to swerve while driving on the high way, to stick that lab equipment in our mouths even when we’re told not to (cough); we can force it back… but those with LNS are unable to fight these dark compulsions.

            And the source of this self-injurious behavior, one that cannot be altered by “nurturing,” is genetic. Now, I must admit that my stance on Nature versus Nurture is somewhere in the middle. While I do think that genes play an important role in determining human behavior, in situations outside of LNS, environmental and developmental factors play a just as important role in determining the character and behavior of a person. Like imprinting in baby geese or that crucial period where young birds learn the songs of the species, environmental and developmental factors contribute quite a bit to the behaviors of an organism. It would be small-minded to think that humans were an exception. And it would be just as ignorant to shrug off the role of genes in determining human behavior. We are complex organisms, with many factors coming into play concerning our person; we tend to give genetic components the short end of the stick when it comes to behavior. Lesch-Nyhan is one of those rare cases that suggests otherwise.

References:

1. http://www.ninds.nih.gov/disorders/lesch_nyhan/lesch_nyhan.htm