Sait Haseena, Srivastava Priyanka, Dabadghao Preeti, Phadke Shubha R
Department of Medical Genetics, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India.
Genetic Metabolic Unit, Department of Pediatrics, Post Graduate Institute of Medical Education and Research, Chandigarh, India.
J Reprod Infertil. 2021 Oct-Dec;22(4):302-306. doi: 10.18502/jri.v22i4.7657.
Xp22.3 region is characterized by low frequency of interspersed repeats and low GC content. Several clinically important genes including ANOS1 (KAL1) reside in this region. This gene was first identified due to translocation between chromosomes X and Y in a patient with Kallmann syndrome.
A 20 year old male presented with complaints of delayed secondary sexual characteristics, impaired sense of smell, and poor scholastic performance. On examination, he had short stature (151 ; <3rd centile). His sexual maturity corresponded to Tanner stage 3. Stretched penile length was 3.6 (<3rd centile). Right testis was undescended with low left testicular volume (12 ). There was mild ichthyosis over abdomen and back. He had hyposmia, hoarse voice, and synkinesia. Investigations were suggestive of hypogonadotrophic hypogonadism. Karyotype revealed an extra chromosomal material on p arm of chromosome X (46,Xp+,Y). On cytogenetic microarray, deletion of 8.3 on Xp22.33 region and duplication of 12.8 on Yq11.22 region were identified. The breakpoint on X chromosome resulted in deletion of exons 7-14 of ANOS1 gene and complete STS, NLGN4X, ARSL (ARSE), SHOX, and VCX genes.
Patients diagnosed with Kallmann syndrome should receive careful clinical evaluation to detect presence of a contiguous gene syndrome.
Xp22.3区域的特点是散布重复序列频率低且GC含量低。包括ANOS1（KAL1）在内的几个临床重要基因位于该区域。该基因最初是在一名卡尔曼综合征患者中因X染色体和Y染色体之间的易位而被鉴定出来的。
一名20岁男性，主诉继发性征发育延迟、嗅觉减退和学业成绩差。检查发现，他身材矮小（身高151cm；低于第3百分位数）。其性成熟度相当于坦纳3期。阴茎拉伸长度为3.6cm（低于第3百分位数）。右侧睾丸未降，左侧睾丸体积小（12ml）。腹部和背部有轻度鱼鳞病。他有嗅觉减退、声音嘶哑和联带运动。检查提示为低促性腺激素性性腺功能减退。核型显示X染色体p臂上有一条额外的染色体物质（46,Xp+,Y）。在细胞遗传学微阵列上，鉴定出Xp22.33区域缺失8.3Mb，Yq11.22区域重复12.8Mb。X染色体上的断点导致ANOS1基因外显子7 - 14以及完整的STS、NLGN4X、ARSL（ARSE）、SHOX和VCX基因缺失。
被诊断为卡尔曼综合征的患者应接受仔细的临床评估，以检测是否存在连续基因综合征。
