Striking anticipation in spinocerebellar ataxia type 7: the infantile phenotype

Somatic spinal reflexes are rapid, involuntary muscular responses to external stimuli that involve the somatic musculature and the spinal cord.
One of the most well-known somatic spinal reflexes is the stretch reflex, which is activated by the sudden stretching of a muscle. This reflex involves the activation of specialized sensory receptors called muscle spindles, which are located in the muscle tissue and detect changes in the length and speed of muscle contractions. When a muscle is suddenly...

Huntington disease or HD is a progressive, fatal neurodegenerative disorder inherited in an autosomal dominant pattern.PathophysiologyIt is caused by expansion of the CAG trinucleotide repeat in the HTT gene on chromosome 4 (4p16.3), producing an abnormal huntingtin protein with an expanded polyglutamine tract. This misfolded protein disrupts cellular function, leading to neuronal death. Normal alleles have ≤26 repeats, 27–35 are intermediate (risk of expansion), 36–39 show reduced penetrance,...

Gestures are nonverbal movements of the hands, arms, or face that allow infants and toddlers to communicate emotions, needs, and intentions before speech develops. Gesture use generally appears before spoken language and decreases as vocabulary expands. For example, an 11-month-old may raise their arms to request being picked up, whereas an 18-month-old may say “up.”Types of GesturesChildren mainly use deictic and representational gestures. Deictic gestures emerge around six months and include...