Albinism and Abnormal Platelet Function

Logan, L. J.; Rapaport, Samuel I.; Maher, Ian A.

doi:10.1056/nejm197106172842402

Cited by 65 publications

(20 citation statements)

References 30 publications

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“…Decreased 5-HT (31,50,51) and adenine nucleotide (50) values have also been reported in other patients who have both albinism and a bleeding disorder, and the findings in the present study suggest that the platelet defects (31,(50)(51)(52) in these patients may differ only in degree from those in patients with "idiopathic" storage pool disease. In addition to the diminished levels of 5-HT and adenine nucleotides, the platelets of patients with storage pool disease and albinism are also deficient in Ca" ' (23) and show diminished numbers of the electron-dense granules (51,53) in which these substances are stored (6-9).…”

Section: Discussionsupporting

confidence: 84%

Studies of Platelet 5-Hydroxytryptamine (Serotonin) in Storage Pool Disease and Albinism

Weiss¹,

Tschopp²,

Rogers³

et al. 1974

J. Clin. Invest.

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A B S T R A C T Platelets in patients with storage pool disease are markedly deficient in a nonmetabolic (storage) pool of ADP that is important in platelet aggregation. They are also deficient in ATP, although to a lesser degree. In seven patients with this disorder, including one with albinism, platelet 5-hydroxytryptamine (5-HT) levels were reduced in proportion to the reduction in ATP (r = 0.94). Their platelets show diminished capacity to absorb ["C] 5-HT, and the type of defect was similar to that produced in normal platelets by reserpine, a drug known to inhibit the uptake of 5-HT by the platelet dense granules. Storage pool-deficient platelets also converted more [8H] 5-HT to [3H] 5-hydroxyindoleacetic acid than did normal platelets, and the platelets in one of two patients studied contained increased amounts of 5-HT metabolites. The above findings, together with those reported previously, support the conclusion that the capacity of the dense granules (which may be either diminished or functionally abnormal) for storing 5-HT is decreased in storage pool disease; as a result, the 5-HT that enters the platelet may be more exposed to monoamine oxidases present on mitochondrial membranes. This diminished storage capacity (for 5-HT) may also explain why preincubating platelet-rich plasma with 5-HT for 45 min without stirring inhibits subsequent platelet aggregation by 5-HT to a greater degree in patients with storage pool disease than in normal subjects. The latter finding is also consistent with the theory that the aggregation of platelets by 5-HT is mediated by the same receptors on the plasma membrane that are involved in its uptake. The diminished release of platelet-bound ["C]5-HT by collagen that we found in these patients, as well as findings in previous studies, suggests that the release reaction may also be abnormal in storage pool disease.

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Section: Discussionsupporting

confidence: 84%

Studies of Platelet 5-Hydroxytryptamine (Serotonin) in Storage Pool Disease and Albinism

Weiss¹,

Tschopp²,

Rogers³

et al. 1974

J. Clin. Invest.

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show abstract

“…In our series normal bleeding times in association with previously described qualitative platelet defects (14,16) were seen with Noonan's syndrome and albinism. Although patients with significant clinical bleeding problems usually have prolonged bleeding times, this time-honored screening test may not be adequate t o detect all cases of qualitative platelet dysfunction.…”

Section: Discussionsupporting

confidence: 86%

“Car. Factor” Deficiency Revisited

Komp

1975

Pediatr Res

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“…1,2 In mice, 16 loci are associated with Hermansky-Pudlak syndrome, including HPS6. The HPS6 gene encodes a novel protein (HPS6) in the biogenesis of lysosome-related organelles complex (BLOC)-2 of HPS3, HPS5, and HPS6, which regulates the synthesis of lysosome-related organelles, including melanosomes and platelet dense granules.…”

Section: Introductionmentioning

confidence: 99%