King R A, Wiesner G L, Townsend D, White J G
Department of Medicine, University of Minnesota, Minneapolis 55455.
Am J Med Genet. 1993 Apr 1;46(1):40-4. doi: 10.1002/ajmg.1320460109.
Chromosome region 15q is thought to contain one or more genes that are important for melanin pigment synthesis in the hair, skin, and eyes. Hypopigmentation has been identified in the Prader-Willi (PWS) and Angelman (AS) syndromes. We have examined 6 individuals with AS to further characterize the pigment pattern in this condition. The age of the 5 girls and one boy ranged from 2.4 to 7.0 years. None had obvious albinism. Hair color ranged from light blond to brown. Skin was type I in 3 and type II in 3. Eye changes included nystagmus in 2, strabismus in 4, and reduced retinal pigment in 5. The mean hairbulb tyrosinase activity was 0.37 +/- 0.44 pmol/hb/120 min for the individuals with AS, with a range of 0.00 to 1.13 (normal brown control 1.49 +/- 0.79, normal blond control 1.50 +/- 0.85). Electron microscopic examination of hairbulb melanocytes showed normal melanosome and melanocyte architecture and number, but reduced melanin formation, with many stage II and III premelanosomes but few stage IV fully melanized melanosomes. Hypopigmentation characterized by light skin, reduced retinal pigment, low hairbulb tyrosinase activity, and incomplete melanization of melanosomes is part of the phenotype of AS, and is similar to that found in PWS.
染色体区域15q被认为包含一个或多个对头发、皮肤和眼睛中黑色素合成至关重要的基因。普拉德-威利综合征（PWS）和安吉尔曼综合征（AS）中已发现色素减退。我们检查了6名患有AS的个体，以进一步描述这种情况下的色素模式。5名女孩和1名男孩的年龄在2.4至7.0岁之间。没有人有明显的白化病。头发颜色从浅金色到棕色不等。3人的皮肤为I型，3人为II型。眼部变化包括2人有眼球震颤，4人有斜视，5人视网膜色素减少。患有AS的个体的平均毛球酪氨酸酶活性为0.37±0.44 pmol/hb/120分钟，范围为0.00至1.13（正常棕色对照为1.49±0.79，正常金色对照为1.50±0.85）。对毛球黑素细胞的电子显微镜检查显示黑素体和黑素细胞的结构及数量正常，但黑色素形成减少，有许多II期和III期前黑素体，但很少有IV期完全黑素化的黑素体。以浅色皮肤、视网膜色素减少、低毛球酪氨酸酶活性和黑素体不完全黑素化为特征的色素减退是AS表型的一部分，并与PWS中发现的情况相似。
