Normal levels of acidic a-man activity have been found in the culture medium of a number of mannosidosis fibroblast 1ines.This observation is different from most other lysosomal storagediseases in which enzyme deficiency is evident both intra-and extracellularly. Studies were undertaken in order to determine if the extracellular a-man is in fact a product of the cells. Cellscultivated in medium containing fetal calf serum from which acidic a-man was removed by concanavalin A adsorption excreted normal amounts of a-man. The extracellular enzyme exhibited normal the^ mostability and normal kinetics. Incubation of mannosidosiaextracellular enzyme with either normal or patient cell lysate resulted in a partial loss of acidic a-man activity whereas an additive, value was observed when the normal extracellular enzyme was incubated with cell lysate of either type. Addition of medium from normal cell cultures to mucolipidosis I1 fibroblasts previously cultured in presence of C 3~1 mannose resulted in reduction of the intracellular storage of mannose-containing macromolecules. In contrast, no correction could be demonstrated with medium from mannosidosis cell cultures. These findings suggest that the mutation in mannosidosis results in altered catalytic properties and thermostability only after complete intracellular processing. The final processing presumably takes place within the lysosomes and the extracellular enzyme which has escaped this step therefore does not express the defect. Clinical features in patients with 9p duplication have been well delineated (de Grouchy 1977). This report is prompted by two patients seen in the Genetics Clinic at University of California Irvine Medical Center and University of California Los Angeles. Upon examination each patient demonstrated the following characteristics: brachycephaly, bulbous nose, worried facial expression, small deep-set eyes, short upper lip, downturned mouth, large external ears, and varying degrees of mental retardation. The chromosomal karyotype in each patient revealed partial 9p duplication, one as a result of tandem duplication of 9p bands (p133p24) and the second patient with an extra number 9 with deletion of the long arm distal to q13. Further study revealed both patients to have elevated galactose-l-phosphateuridyl-transferase (GALT) levels.These two patients demonstrate two significant observations: 1) the presence of minor dysmorphic features and varying mental retardation occurring with duplication of all or a segment of 9p; 2) the elevated levels of GALT certainly aided the interpretation of unusual chromosomal abnormalities. Fibrodysplasia ossificans progressiva (FOP) is a rare heritable disorder characterized by the progressive accumulation of heterotopic bone arising in the connective tissues of skeletal muscle, ligaments, and tendons. Although the mechanism underlying the formation of heterotopic bone in FOP is at present undefined, the format5on of cartilage and bone in soft tissue is preceded by the appearance of proliferating fibroblastic-li...

The gene for superoxide dismutase-1 (SOD-1) is clearly on chromosome 21, although there is disagreement on the precise band location of SOD-1 on the long (q) arm of number 21. We report a patient with normal superoxide dismutase-1 (SOD-1) activity and an interstitial deletion of chromosome 21 resulting in monosomy for band q21. His phenotype is characterized by moderate mental retardation, a long narrow face, high and arched palate, cardiac murmur, undescended testes, and long hyperflexible extremities. The normal SOD-1 activity supports localization of this enzyme to 21q22.1.

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