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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.
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Human chromosomal micro-deletions and behavior |
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Behavioral landmark |
Microdeletion |
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Eating disorder |
15 (Prader Willi) |
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Indifference to pain and sleep disorder |
17p11.2 (Smith Magenis) |
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Schizophreniform obsessive |
22q11 (Ryan et al.) |
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Loquaciousness and love of music |
7q11.23 (Williams Syndrome) |
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Some Canine Disorders with Strong Genetic Basis |
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| Cardiomyopathy | Boxer |
| Epilepsy | Beagles, St. Bernards |
| Myasthenia Gravis | Chihuahuas, Scot. Terriers |
| Narcolepsy | Doberman pinschers |
| Spinal Muscular Atrophy | Spaniels |
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21/January/2002 dc
