de Vries B B, Fryns J P, Butler M G, Canziani F, Wesby-van Swaay E, van Hemel J O, Oostra B A, Halley D J, Niermeijer M F
Department of Clinical Genetics, University Hospital Dijkzigt, Erasmus University, Rotterdam, The Netherlands.
J Med Genet. 1993 Sep;30(9):761-6. doi: 10.1136/jmg.30.9.761.
A special subphenotype of the fragile X syndrome is reported which is characterised by extreme obesity with a full, round face, small, broad hands/feet, and regional skin hyperpigmentation. It resembles the Prader-Willi syndrome (PWS) and might therefore be named 'Prader-Willi-like'. Unlike the PWS, these PW-like fragile X patients lack the neonatal hypotonia with feeding problems during infancy followed by hyperphagia from toddlerhood. We describe five new fragile X patients and present a clinical update of three previously described patients with the PW-like phenotype. In one family, segregation of either the classical Martin-Bell or the PW-like phenotype was observed and in another family there was repeated transmission of the PW-like phenotype. Previously, one of the patients had been misdiagnosed as having classical PWS, based on clinical findings. Molecular studies of the FMR-1 gene showed the typical full mutations as seen in fragile X syndrome males. Molecular analysis of the 15q11-13 region, which is deleted in the majority of classical PWS patients, did not show any detectable abnormalities. In a group of 26 patients with suspected Prader-Willi syndrome but without detectable molecular abnormalities of chromosome 15, one fragile X patient was found. These clinical and molecular findings illustrate the necessity to perform DNA analysis of the FMR-1 gene in mentally retarded patients presenting with a PW phenotype but without the PWS specific cytogenetic/molecular abnormalities of chromosome 15.
据报道，脆性X综合征存在一种特殊的亚表型，其特征为极度肥胖、圆脸饱满、手脚短小宽阔以及局部皮肤色素沉着。它类似于普拉德-威利综合征（PWS），因此可能被命名为“类普拉德-威利综合征”。与PWS不同的是，这些类普拉德-威利综合征的脆性X患者在婴儿期不存在伴有喂养问题的新生儿肌张力减退，也不会在幼儿期出现贪食症。我们描述了5例新的脆性X患者，并介绍了3例先前描述的具有类普拉德-威利综合征表型患者的临床最新情况。在一个家族中，观察到了经典的马丁-贝尔表型或类普拉德-威利综合征表型的分离，在另一个家族中，类普拉德-威利综合征表型出现了反复传递。此前，有一名患者根据临床检查结果被误诊为患有经典的PWS。FMR-1基因的分子研究显示出脆性X综合征男性中常见的典型完全突变。对15q11 - 13区域的分子分析（大多数经典PWS患者该区域存在缺失）未发现任何可检测到的异常。在一组26例疑似普拉德-威利综合征但未检测到15号染色体分子异常的患者中，发现了1例脆性X患者。这些临床和分子研究结果表明，对于表现出类普拉德-威利综合征表型但不存在15号染色体PWS特异性细胞遗传学/分子异常的智障患者，进行FMR-1基因的DNA分析是必要的。
