Tunis Med. 2021 Feb;99(2):302-305.
We report a special case of a patient who presented with two rare genetic diseases, Turner syndrome and cone-rod dystrophy (CRD), caused by mutation in the ABCA4 gene.
We present a case of a 12-year-old female with a progressive visual loss, poor night vision and short stature. We performed a clinical, karyotype of peripheral blood and molecular genetic study. DNA sample from the index patient was subjected to whole exome sequencing. Variants localized in homozygous regions were validated by Sanger sequencing.
Fundus examination presented CRD phenotype and the general examination revealed short stature, aortic coarctation and infantile uterus, without visible ovaries on pelvic ultrasound. The karyotype of peripheral blood showed monosomy 45,X. We identified a known homozygous deletion c.[885delC];[885delC] in ABCA4, resulting in a frameshift at the position p.[L296Cfs4];[ L296Cfs4] . In addition, mutations in RPGR and ORF15 were excluded.
Several ocular disorders are known to be associated with Turner syndrome, however, in this case, we hypothesize that CRD is not related to Turner syndrome but may be a manifestation of the lack of a normal X chromosome with ABCA4 mutation.
我们报告了一例同时患有两种罕见遗传病特纳综合征和 Cone-rod 营养不良（CRD）的特殊病例，该病例由 ABCA4 基因突变引起。
我们报告了一例 12 岁女性患者，其表现为进行性视力丧失、夜视不良和身材矮小。我们进行了临床、外周血核型和分子遗传学研究。对索引患者的 DNA 样本进行了全外显子组测序。通过 Sanger 测序验证定位在纯合区域的变异。
眼底检查表现为 CRD 表型，全身检查显示身材矮小、主动脉缩窄和幼稚子宫，盆腔超声未见可见卵巢。外周血核型显示单体性 45,X。我们在 ABCA4 中发现了一个已知的纯合缺失 c.[885delC];[885delC]，导致位置 p.[L296Cfs4];[ L296Cfs4]的移码。此外，排除了 RPGR 和 ORF15 的突变。
已知几种眼部疾病与特纳综合征有关，但在本例中，我们假设 CRD 与特纳综合征无关，而可能是 ABCA4 突变导致正常 X 染色体缺失的表现。
