Molecular Investigations of the RCCX module in Congenital Adrenal Hyperplasia

RCCX区域具有多个假基因和串联重复序列，其在减数分裂期间促进错配，导致复杂的基因重排、缺失和基因转换事件。CYP 21 A2突变导致先天性肾上腺增生（CAH），TNX缺乏被认为是活动过度的Ehlers Danlos综合征（EDS）的原因。使用Southern印迹、基于PCR的缺失检测和感兴趣外显子的直接测序，研究了在国家儿童健康与发展研究所根据方案06 CH 001观察到的CAH患者队列和在国家老龄研究所根据方案2003-086观察到的EDS患者队列中RCCX模块的结构。在CAH队列中34.7%的先证者染色体中检测到CYP 21 A2缺失，其中15%的缺失延伸到TNXB。通过Southern Blot分析，确定了独特的单倍型，包括3个CAH先证者与CYP 21 A2的三倍体，一个同胞对与TNXB缺失和CYP 21 A2的三倍体。一个新的杂合子30 kB TNXB缺失，没有延伸到CYP 21 A2被发现在一个家庭与高流动性形式的EDS。一份详细描述受CAH和TNX缺失影响的患者的临床特征的手稿，包括逆位、四价主动脉瓣、双瓣悬雍垂裂开和双角子宫，已被《美国医学遗传学杂志》A部分接受发表，并处于微小修订的最后阶段。临床结果使我们得出结论，那些盐消耗型CAH有严重的发育畸形和异常的关节发现。进一步的研究，包括RT-PCR和免疫化学方法来研究TNXB表达和细胞外基质组织，正在进行中，以更好地确定这种新的CAH-TNX（CAH-X）连续性基因缺失综合征的临床，分子和生化方面。 它代表了遗传性结缔组织疾病与内分泌疾病的交叉。

The RCCX region has multiple pseudogenes and tandem repeat sequences that promote misalignment during meiosis leading to complex gene rearrangements, deletions and gene conversion events. CYP21A2 mutations cause Congenital Adrenal Hyperplasia (CAH) and TNX deficiency has been proposed as a cause of hypermobile Ehlers Danlos syndrome (EDS). The structure of the RCCX module in a cohort of patients with CAH seen at the National Institute of Child Health and Development under Protocol 06CH001, and in patients with EDS seen at the National Institute on Aging under protocol 2003-086 has been investigated using Southern blotting, PCR-based detection of deletions, and direct sequencing of exons of interest. CYP21A2 deletions were detected in 34.7% of the proband chromosomes in the CAH cohort, and 15% of those had a deletion extending into TNXB. Unique haplotypes, including three CAH probands with triplication of CYP21A2, a sibling pair with a deletion of TNXB and triplication of CYP21A2, were identified through Southern Blot analysis. A novel heterozygous 30 kB TNXB deletion that did not extend into CYP21A2 was found in a family with hypermobile form of EDS. A manuscript detailing the clinical features of patients affected by CAH and TNX deletion included situs inversus, quadrivalent aortic valve, bifid split uvula and bicorneate uterus has been accepted for publication in American Journal of Medical Genetics Part A and is in final stages of minor revision. Clinical findings led us to conclude that those with a salt-wasting form of CAH have severe developmental malformations and abnormal joint findings. Further studies, including RT-PCR and immunochemistry approach to study the TNXB expression and extracellular matrix organization, are under way to better define the clinical, molecular and biochemical aspects of this novel CAH-TNX (CAH-X) Contiguous Gene Deletion Syndrome. It represents an intersection of hereditary connective tissue disorders with an endocrine disorder.