metachromatic leukodystrophy

an autosomal recessive disorder (see recessive allele) characterized by deficiency or absence of the enzyme arylsulfatase A, which results in loss of myelin in the nervous system and accumulation of cerebroside sulfate (a type of myelin lipid) within the white matter of the central nervous system. Loss of motor function and deterioration in mental ability most commonly develop after the 1st year of life (late infantile form), but symptoms may also appear between 3 and 10 years of age (juvenile form) or around age 30 (adult form).

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Psychology term of the day

January 31st 2025

Kretschmer typology

a controversial classification of individuals based on a “clear biological affinity” between specific physiques and specific personality tendencies. According to this classification, the short, stocky pyknic type tends to be jovial and subject to mood swings; the frail asthenic type is likely to be introversive and sensitive; the muscular athletic type is usually energetic and aggressive; and the disproportioned dysplastic type presents a combination of traits but tends toward the asthenic. These tendencies were attributed to endocrine secretions. [formulated in the 1920s by German psychiatrist Ernst Kretschmer (1888–1964)]