RESUMO
Hermansky-Pudlak syndrome (HPS) (MIM #203300) is a heterogeneous group of autosomal recessive disorders characterized by oculocutaneous albinism (OCA), bleeding tendency, and lysosomal dysfunction. HPS is very common in Puerto Rico (PR), particularly in the northwest part of the island, with a frequency of approximately 1:1,800. Two HPS genes and mutations have been identified in PR, a 16-base pair (bp) duplication in HPS1 and a 3,904-bp deletion in HPS3. In Puerto Ricans with more typical OCA, the most common mutation of the tyrosinase (TYR) (human tyrosinase (OCA1) gene) gene was G47D. We describe screening 229 Puerto Rican OCA patients for these mutations, and for mutations in the OCA2 gene. We found the HPS1 mutation in 42.8% of cases, the HPS3 deletion in 17%, the TYR G47D mutation in 3.0%, and a 2.4-kb deletion of the OCA2 gene in 1.3%. Among Puerto Rican newborns, the frequency of the HPS1 mutation is highest in northwest PR (1:21; 4.8%) and lower in central PR (1:64; 1.6%). The HPS3 gene deletion is most frequent in central PR (1:32; 3.1%). Our findings provide insights into the genetics of albinism and HPS in PR, and provide the basis for genetic screening for these disorders in this minority population.
Assuntos
Albinismo Oculocutâneo/genética , Proteínas de Transporte/genética , Testes Genéticos , Síndrome de Hermanski-Pudlak/genética , Proteínas de Membrana/genética , Adolescente , Adulto , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Recém-Nascido , Peptídeos e Proteínas de Sinalização Intracelular , Masculino , Proteínas de Membrana Transportadoras/genética , Pessoa de Meia-Idade , Monofenol Mono-Oxigenase/genética , Mutação , Porto Rico , Deleção de SequênciaRESUMO
BACKGROUND: Hermansky-Pudlak syndrome (HPS) is a common genetic disorder in Puerto Rico. In children with HPS, bleeding is the most disturbing and incapacitating problem. Desmopressin (1-deamino-8-D-arginine vasopressin, (DDAVP)) has been recommended in the management of bleeding disorders characterized by platelet dysfunction, such as HPS. METHODS: Nineteen pediatric Puerto Rican patients with HPS and prolonged bleeding time (BT) were tested for response to administration of DDAVP. RESULTS: Baseline BT was abnormal in 18 (95%) of the patients. The BT following DDAVP administration improved in two cases (11%): one from 7.2 to 5.6 min and the other from 8 to 6 min (Tables II and III). BT measurements remained very prolonged (>15 min) in 17 (89%) of the patients. Patients with the HPS 1 gene mutation had a statistically significant correlation with the poor response following DDAVP (P = 0.03). CONCLUSIONS: DDAVP seldom improves the BT of Puerto Rican children with HPS. Response to DDAVP should be determined individually and platelet transfusion should remain the treatment of choice for a major bleeding episode or surgical procedure.