Lacbawan F L, White B J, Anguiano A, Rigdon D T, Ball K D, Bromage G B, Yang X, DiFazio M P, Levin S W
Medical Genetics Branch, NHGRI, the National Institutes of Health, Bethesda, Maryland, USA.
Am J Med Genet. 1999 Nov 19;87(2):139-42.
An unbalanced 46,XY,der(2)del(2)(p11.2p13) inv(2)(p11.2q13) karyotype was found in a phenotypically abnormal child with a de novo interstitial deletion of band 2p12 associated with an inv(2)(p11.2q13) inherited from the father. The inv(2) is generally considered a benign familial variant without significant reproductive consequences. However, our findings led us to consider a previously proposed mechanism of unequal meiotic crossing over at the base of a parental inversion loop, which could lead to either a deletion or duplication of a segment adjacent to the inverted region in the offspring. This phenomenon has been reported in other inversions of chromosomes 1, 7, 13, 15, and 17 and may explain the origin of the deletion in our patient. Although repetitive sequences might be present around such inversions, which could predispose to de novo deletions independently of the inversion, current evidence including this case favors a proposed causal relationship between the parental inversion and the deletion in the child. Our review and results suggest there could be a small risk for a related imbalance to couples with an inv(2)(p11.2q13). For del(2)(p11.2p13), which is rare, a more distinct phenotype has been proposed herein. Our patient shared several findings with the three previously published cases, namely the broad nasal bridge, abnormal ears, high-arched palate, psychomotor retardation, and micrognathia. However, our patient also had sensorineural hearing loss and significant hypotonia, which have not been previously reported, thereby expanding our understanding of this rare deletion. Am. J. Med. Genet. 87:139-142, 1999. Published 1999 Wiley-Liss, Inc.
在一名表型异常的儿童中发现了一种不平衡的46,XY,der(2)del(2)(p11.2p13)inv(2)(p11.2q13)核型，该儿童有一个新发生的2p12带间质性缺失，并从父亲那里遗传了inv(2)(p11.2q13)。inv(2)通常被认为是一种良性家族性变异，没有显著的生殖后果。然而，我们的研究结果使我们考虑到一种先前提出的机制，即在亲本倒位环的基础上发生不等减数分裂交叉，这可能导致后代中与倒位区域相邻的片段缺失或重复。这种现象在染色体1、7、13、15和17的其他倒位中也有报道，可能解释了我们患者中缺失的起源。尽管此类倒位周围可能存在重复序列，这可能独立于倒位而导致新的缺失，但包括本病例在内的现有证据支持亲本倒位与儿童缺失之间存在因果关系。我们的综述和结果表明，携带inv(2)(p11.2q13)的夫妇可能存在相关不平衡的小风险。对于罕见的del(2)(p11.2p13)，本文提出了一种更独特的表型。我们的患者与之前发表的三个病例有几个共同的发现，即宽鼻梁、耳朵异常、高拱腭、精神运动发育迟缓以及小颌畸形。然而 our patient also had sensorineural hearing loss and significant hypotonia, which have not been previously reported, thereby expanding our understanding of this rare deletion. Am. J. Med. Genet. 87:139 - 142, 1999. Published 1999 Wiley - Liss, Inc.（此处英文原文有误，正确的应该是“然而，我们的患者还患有感音神经性听力损失和明显的肌张力减退，这在之前未曾报道过，从而扩展了我们对这种罕见缺失的认识。《美国医学遗传学杂志》87:139 - 142, 1999。1999年由威利 - 利斯公司出版。”） 我们的患者还患有感音神经性听力损失和明显的肌张力减退，这在之前未曾报道过，从而扩展了我们对这种罕见缺失的认识。《美国医学遗传学杂志》87:139 - 142, 1999。1999年由威利 - 利斯公司出版。
