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    Highlights                             by W. Wertelecki, MD                     December 1999    
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Models for Human Cognition and Behavior
Williams Syndrome (WS) - LIMK1 and STX1A genes - The Dog Genome Project - Narcolepsy - Cataplexy - Doberman Pinschers

Human chromosomal microdeletions provide a tool to dissect physical, cognitive and emotional phenotypes. Among the genes affected by the 7q11.23 microdeletion associated with WS are ELN (which encodes for elastin), LIMK1 (which encodes for a protein tyrosine kinase expressed in developing brains), STX1A (which encodes a component in the synaptic apparatus, and FZD3). Other human microdeletion syndromes also have strong behavioral components (table below).

According to investigations by Dr. M. Tassabehji et al.(Am. J. Hum. Genet. 64: 118, 1999) that concentrated on WS patients with ELN hemizygosity, anomalies in elastin are responsible for the cardiological features of WS. Others investigators proposed that the LIMK1 and STX1A genes are "good candidates" for cognitive or behavioral traits of WS. Furthermore, the investigators found that neither LIMK1 nor STX1A are likely to contribute to any part of the WS phenotype. The relative abundance of patients with WS and of active WS parental support organizations are likely to spur other investigators to enter the arena.

Dogs and humans are close companions. Who adopted or domesticated whom may be debatable. Be this as it may, a number of canine disorders have close human analogues. Easy access to dogs with defined and distinct behaviors and the possibility to control dog matings have stimulated research of the genetic basis of behaviors. Recently, Drs. E. Ostrander (Fred Hutchinson Cancer Research Center in Seattle) and M. Neff (University of California at Berkeley) produced a map of the dog genome.

Among the array of canine genetic defects under study is narcolepsy, a sleep disorder that affects nearly 1 in 2000 Americans. Often, the disorder is not recognized and the diagnosis delayed. The signature manifestation of narcolepsy is cataplexy - the sudden loss of muscle control triggered by emotional stimuli. The clinical similarities of canine and human narcolepsy are remarkable. Other canine disorders with human equivalents are being intensely investigated.

Human chromosomal micro-deletions and behavior

Behavioral landmark


Eating disorder

15 (Prader Willi)

Indifference to pain and sleep disorder

17p11.2 (Smith Magenis)

Schizophreniform obsessive

22q11 (Ryan et al.)

Loquaciousness and love of music

7q11.23 (Williams Syndrome)

Some Canine Disorders with Strong Genetic Basis

Cardiomyopathy Boxer
Epilepsy Beagles, St. Bernards
Myasthenia Gravis Chihuahuas, Scot. Terriers
Narcolepsy Doberman pinschers
Spinal Muscular Atrophy Spaniels

Williams Syndrome

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21/January/2002 dc