Aim

Hyperphosphatemic familial tumoral calcinosis (HFTC) is a rare endocrine disorder caused by autosomal recessive variants in GALNT3, FGF23, and KL leading to progressive calcification of soft tissues and subsequent clinical effects. The aim of this was to study the cause of HFTC in an Iranian family.

Patients and methods

Four generations of a family with HFTC were studied for understanding the genetic pattern of the disease. Whole exome sequencing was applied on genomic DNA of the proband. Based on its result, genetically altered sequences were checked in his family through sanger sequencing. Then bioinformatics approaches as well as co-segregation analysis were applied to validate the genetic alteration.

Results

A novel homozygous variant in exon four of GALNT3, namely p.R261Q was found. The parents and sister were carriers.

Conclusion

To our knowledge, it is the first-reported Iranian family with GALNT3-CDG novel variant.

中文翻译：

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由 GALNT3 基因的新变异引起的高磷血症家族性肿瘤钙质沉着症。

 目的

高磷血症家族性肿瘤钙质沉着症 (HFTC) 是一种罕见的内分泌疾病，由GALNT3、FGF23和KL的常染色体隐性变异引起，导致软组织进行性钙化和随后的临床影响。其目的是研究伊朗家庭中 HFTC 的原因。

 患者和方法

为了了解该疾病的遗传模式，我们对一个患有 HFTC 的家庭的四代人进行了研究。对先证者的基因组DNA进行全外显子组测序。根据其结果，通过桑格测序在他的家人中检查了基因改变的序列。然后应用生物信息学方法以及共分离分析来验证遗传改变。

 结果

在GALNT3的第四外显子中发现了一个新的纯合变异，即 p.R261Q。父母和姐姐都是携带者。

 结论

据我们所知，这是第一个报道的伊朗家族携带 GALNT3-CDG 新型变异体。