ALPL基因突变导致成年型低磷酸酶症一家系研究

Adult hypophosphatasia caused by ALPL mutation： one pedigree study

本研究分析由肝/骨/肾型碱性磷酸酶（alkaline phosphatase, liver /bone /kidney, ALPL）基因突变引起的低磷酸酶症一家系患者及其家庭成员的临床特征,旨在提高对本病的认识.该家系先证者及其姐姐血清碱性磷酸酶（ALP）水平均处于正常范围下限,四肢反复发生骨折,牙齿过早脱落.先证者及其姐姐ALPL基因均为复合杂合突变,2个突变位点分别为5号外显子的错义突变c.407G〉A（p.Arg136His）和12号外显子的杂合缺失c.1318_1320delAAC（p.Asn440del）.其他家庭成员均为杂合突变,4例成员的突变位点为p.Arg136His,2例成员的突变位点为p.Asn440del,其中突变位点p.Asn440del与患者的口腔疾病相关.在该家系中,2例严重症状者均为复合杂合子,其他杂合子症状较轻,低磷酸酶症需与原发性骨质疏松症或其他骨骼矿化障碍疾病鉴别.

An adult patient with hypophosphatasia caused by compound heterozygous mutations in alkaline phosphatase,liver /bone /kidney（ALPL）gene was investigated through comprehensively reviewing the medical history and clinical records of the proband and her family members in order to better understand the disease.The proband and her older sister had mild decreased serum alkaline phosphatase level accompanied with frequently nontraumatic fractures at limbs and all the teeth fell off at the age of 20 and 7, respectively.Both of them carried a missense mutation c.407G〉A（p.Arg136His）in exon 5 and a deletion mutation c.1318_1320delAAC（p.Asn440del）in exon 12 simultaneously.Other four family members were p.Arg136His mutation carriers and two members were p.Asn440del mutation carriers.We found that p.Asn440del mutation was associated with the oral disorders.In this family, compound heterozygous manifested more serious symptoms, while heterozygous showed relatively mild symptoms.In addition, it is necessary to differentiate it from primary osteoporosis and other diseases of disturbed bone mineralization.