Mensink E J, Thompson A, Schot J D, Kraakman M E, Sandkuyl L A, Schuurman R K
Clin Genet. 1987 Feb;31(2):91-6. doi: 10.1111/j.1399-0004.1987.tb02775.x.
X-linked agammaglobulinemia (XLA) is a severe antibody deficiency disease reflecting an arrest of B lymphocyte differentiation at the level of precursor B cells. The disease is inherited in an X-linked recessive mode. In a single eight-generation pedigree the XLA gene was mapped to the Xq21.3-Xq22 area of the X chromosome. The data establish close linkage of the XLA locus to the DXS17 restriction fragment length polymorphic (RFLP) marker locus (the lod score exceeding 6 at phi = 0). A series of RFLP markers around the DXS17 locus provided an RFLP haplotype of use in genetic counselling within this pedigree. In one other pedigree a phenotypically identical disease was inherited but was accompanied by a high frequency of recombination with the DXS17 locus, which made localisation of the gene at the DXS17 locus highly unlikely (lod score less than -3). This genetic heterogeneity complicates genetic counselling within particular pedigrees, especially when the localization of the XLA gene involved in those pedigrees has not been established.
X连锁无丙种球蛋白血症（XLA）是一种严重的抗体缺陷疾病，反映了B淋巴细胞在前体B细胞水平的分化停滞。该疾病以X连锁隐性模式遗传。在一个单一的八代家系中，XLA基因被定位到X染色体的Xq21.3 - Xq22区域。这些数据确定了XLA基因座与DXS17限制性片段长度多态性（RFLP）标记基因座紧密连锁（在φ = 0时，连锁值超过6）。DXS17基因座周围的一系列RFLP标记提供了一种RFLP单倍型，可用于该家系的遗传咨询。在另一个家系中，一种表型相同的疾病被遗传，但与DXS17基因座的重组频率很高，这使得该基因在DXS17基因座定位的可能性极小（连锁值小于-3）。这种遗传异质性使特定家系的遗传咨询变得复杂，尤其是当涉及那些家系的XLA基因定位尚未确定时。
