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浙江大学学报（医学版）
J Zhejiang Univ (Med Sci)  2020, Vol. 49 Issue (5): 556-564    DOI: 10.3785/j.issn.1008-9292.2020.10.02
    
Screening and clinical analysis of isovaleric acidemia newborn in Zhejiang province
HU Zhenzhen1(),YANG Jianbin1,HU Lingwei1,ZHAO Yunfei2,ZHANG Chao1,YANG Rulai1,HUANG Xinwen1,*()
1. Department of Genetics and Metabolism, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, National Regional Medical Center for Children, Hangzhou 310052, China
2. Department of Pediatrics, Taizhou Matemal and Child Health Hospital, Taizhou 318000, Zhejiang Province, China
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Abstract  

Objective: To investigate the incidence, clinical, biochemical and genetic characteristics of isovaleric acidemia (IVA) in Zhejiang province. Methods: Between January 2009 and December 2019, a total of 3 510 004 newborns were screened for IVA using tandem mass spectrometry. Patients of IVA were confirmed by urine organic acid and IVD gene detection. IVA patients were given diet and life management, supplemented with L-carnitine and glycine treatment, long-term followed up to observe and evaluate the growth and intellectual development. Results: A total of 15 patients with IVA were diagnosed, with an incidence of 1/234 000. Three patients had acute neonatal IVA, and the rest were asymptomatic. The isovalerylcarnitine (C5) levels were increased in all patients. Twelve children underwent urinary organic acid analysis, of which 11 cases had elevated isovalerylglycine levels, 4 cases with 3-hydroxyisovalerate increased simultaneously. Eleven IVA patients underwent genetic testing, 9 patients were compound heterozygous variants in IVD gene, one with homozygous variants in IVD gene, and one harbored one IVD variant. Nineteen IVD variants (14 missense mutations, 3 intron mutations, 1 code shift mutation, and 1 synonymous mutation) were identified, 11 of which were not reported. Among the 15 IVA patients, one patient died and two patients were followed up locally. The remaining patients had no obvious clinical symptoms during the follow-up (2-79 months). Three patients presented with growth and development delay, the remaining had normal physical and mental development. Conclusions: The clinical manifestations of IVA are non-specific, and the gene spectrum is scattered. Newborn patients screened by tandem mass spectrometry can receive early diagnosis and treatment, so as to correct metabolic defects and pathophysiological changes.

Key words： Isovaleric acidemia      IVD gene      Neonatal screening      Tandem mass spectrometry      Prevalence rate      Genotype      Phenotype     
Received: 12 May 2020      Published: 19 November 2020
CLC:  R722.11  
Corresponding Authors: HUANG Xinwen     E-mail: hzz22980825@zju.edu.cn;6305022@zju.edu.cn
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HU Zhenzhen
YANG Jianbin
HU Lingwei
ZHAO Yunfei
ZHANG Chao
YANG Rulai
HUANG Xinwen
Cite this article:

HU Zhenzhen,YANG Jianbin,HU Lingwei,ZHAO Yunfei,ZHANG Chao,YANG Rulai,HUANG Xinwen. Screening and clinical analysis of isovaleric acidemia newborn in Zhejiang province. J Zhejiang Univ (Med Sci), 2020, 49(5): 556-564.

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http://www.zjujournals.com/med/10.3785/j.issn.1008-9292.2020.10.02     OR     http://www.zjujournals.com/med/Y2020/V49/I5/556


浙江省新生儿异戊酸血症筛查及临床分析

目的: 了解浙江省新生儿异戊酸血症（IVA）的患病率、临床特征及基因突变特点。方法: 采用串联质谱技术对2009年1月至2019年12月浙江省新生儿疾病筛查中心的3 510 004名新生儿进行遗传代谢病筛查，结合尿有机酸分析及IVD基因检测进行IVA诊断。IVA确诊患儿进行饮食和生活管理，补充左卡尼汀和甘氨酸治疗，长期随访观察并评估患儿的生长和智能发育情况。结果: 共确诊IVA患儿15例，3例为急性新生儿型，其余无临床症状，患病率为1/234 000。所有患儿的血异戊酰基肉碱浓度均不同程度增加。12例患儿进行尿有机酸分析，其中11例异戊酰甘氨酸升高，4例伴3-羟基异戊酸升高。11例患儿进行基因检测，9例为IVD基因复合杂合突变，1例为IVD基因纯合突变，1例只检测出一个IVD基因位点。发现IVD基因突变19种（错义突变14种、内含子突变3种、移码突变1种、同义突变1种），其中11种突变未见报道。15例患儿中1例死亡，2例在当地随访，其余暂未发现明显临床症状（随访时间2~79个月），其中3例生长发育落后，其他患儿体格和智力发育均正常。结论: IVA临床表现无特异性，基因谱分散。使用串联质谱开展IVA新生儿筛查，实现早期诊断和治疗能纠正代谢缺陷及其引发的病理生理改变。


关键词： 异戊酸血症,  IVD基因,  新生儿筛查,  串联质谱法,  患病率,  基因型,  表型 
例序 性别 确诊时间 随访时间 临床症状 疾病分型 随访和预后情况
“—”：无相关资料.
1 女 2月龄 45个月 无 代谢轻型 生长发育落后
2 女 1月龄 79个月 无 代谢严重型 正常
3 男 13月龄 38个月 无 代谢轻型 正常
4 女 17日龄 2个月 无 代谢严重型 正常
5 男 59月龄 59个月 无 代谢轻型 正常
6 男 17日龄 46个月 尿液异味 代谢严重型 生长发育落后
7 男 13日龄 46个月 少哭、少吃、少动，尿液异味 急性新生儿型、代谢严重型 正常
8 男 15日龄 — 少哭、少吃、少动 急性新生儿型、代谢严重型 出生后第7天死亡
9 男 2月龄 11个月 无 代谢轻型 正常
10 男 10日龄 — 无 代谢严重型 当地确诊随访
11 男 21日龄 25个月 无 代谢严重型 生长发育落后
12 女 25日龄 18个月 无 代谢严重型 正常
13 女 28日龄 12个月 无 代谢严重型 正常
14 女 28日龄 14个月 少哭、少吃、少动，尿液异味 急性新生儿型、代谢严重型 正常
15 女 24日龄 7 d 无 代谢严重型 当地确诊随访
Tab 1 Clinical data of 15 patients with isovaleric acidemia
例序 血异戊酰基肉碱(μmol/L) 血游离肉碱(μmol/L) 异戊酰甘氨酸(mmol/mol肌酐) 3-羟基异戊酸(mmol/mol肌酐) 白细胞计数(×109/L) 红细胞计数(×1012/L) 血红蛋白量(g/L) 血小板计数(×109/L) 高血氨 酸中毒 肝损害
初筛 随访 初筛 随访
“—”：无相关资料.*低于正常值下限.
1 0.86 0.99~2.97 50.71 23.97~70.25 4.40 0.00 8.60 3.93 123 506 阳性 阳性 阳性
2 2.12 1.47~8.26 15.49 13.66~53.39 30.29~234.70 0.00~4.87 8.59 3.74 103* 591 阳性 阴性 阴性
3 2.09 0.95~2.38 57.35 28.59~40.71 7.78 0.00 7.61* 3.69* 126* 290 阳性 阴性 阴性
4 8.46 8.39~8.71 24.85 9.35~33.74 316.20~1136.00 5.59~2141.00 7.74 3.75 133 276 阳性 阳性 —
5 1.74 0.40~1.28 47.13 22.74~42.39 0.00 0.00 9.22 3.62 116 301 阴性 阳性 阴性
6 6.13 4.65~12.05 11.31 9.64~41.46 76.52~799.10 0.00~1.18 6.92* 4.25* 130* 255 阴性 阴性 阴性
7 11.12 2.93~18.35 17.30 10.58~87.87 14.07~41.69 0.00 2.83* 3.66* 129* 26* 阳性 阳性 阴性
8 9.85 — 22.17 — — — — — — — 阳性 — —
9 0.66 0.49~2.50 15.69 21.65~60.08 8.74 1.30 4.83* 3.05* 105* 214 阳性 阴性 阴性
10 9.13 — 18.19 — — — — — — — — — —
11 7.43 1.52~7.43 16.43 13.13~52.98 18.75~80.45 0.42~2.01 9.79 4.23 132 234 阳性 阴性 阴性
12 11.34 6.78~16.20 16.40 3.52~21.11 109.65~285.41 1.16~91.11 5.25* 3.65* 119* 51* — 阴性 阴性
13 9.36 3.93~17.13 30.97 28.26~85.83 52.55 2.22 10.49* 3.06* 109* 363 阳性 阴性 阴性
14 11.17 5.31~17.16 15.52 31.57~62.40 276.00 54.00 5.70* 4.64* 144* 35* 阳性 阴性 阴性
15 14.50 6.78 7.17 2.96 — — — — — — — — —
Tab 2 Laboratory data of 15 patients with isovaleric acidemia
例序 核苷酸改变 基因位置 人群频率 氨基酸改变 有害性预测 保守指数(%)
1000 Genomes ExAC gnomAD SIFT PROVEAN PolyPhen-2 HDIV PolyPhen-2 HVAR fathmm Mutation-Taster Human Splicing Finder
“—”：无相关资料.IVD参考序列：NM_002225.3.D:潜在有害、有害或致病；P：可能有害；N：中性；B：良性；T：可容忍；Y：剪切改变；保守指数：将人类IVD氨基酸序列与其他8个物种进行比较，该位点同为人类IVD野生型氨基酸的比例；加粗字体为新突变.

2		 c.340G>C 外显子4 — — — V114L D N B B D D — 67
c.1208A>G 外显子12 — 1.60×10-5 1.62×10-5 Y403C D D D P D D — 100
3 c.134T>G 外显子1 — — — L45R D D D D D D — 100
c.640A>G 外显子6 — 8.00×10-6 1.62×10-5 T214A D D D D D D — 100
5 c.302A>G 外显子4 — — — Y101C D D P B D D — 67
c.1147+5G>A 内含子1 — — — — — — — — — — Y —
6 c.1184G>T 外显子12 — — — R395L D D D D D D — 100
c.1232A>C 外显子12 — — — E411A D D D D D D — 100
7 c.466-2A>G 内含子4 — — — — — — — — — — Y —
c.877G>T 外显子8 — — — G293W D D D D D D — 100
8 c.359G>A 外显子4 — 8.00×10-6 4.06×10-6 R120Q D D D D D D — 100
c.476G>C 外显子5 — — — G159A D D D D D D — 100
9 c.487G>A 外显子5 — — 4.06×10-6 G163R D D D D D D — 100
11 c.1015T>C 外显子10 — — — C339R D D D D D D — 77
12 c.1189_1190delCT 外显子12 — — — L397Sfs*7 — — — — — — — —
c.1019G>A 外显子10 3.99×10-4 4.10×10-5 2.03×10-5 R340Q D D D D D D — 100
13 c.640A>G 外显子6 — 8.00×10-6 1.62×10-5 T214A D D D D D D — 100
c.667C>T 外显子6 — 4.06×10-6 5.80×10-5 R223W D D D P D D — 100
c.296-10C>G 内含子3 — — — — — — — — — — Y —
c.123A>C 外显子1 — — — A41A T N — — — D Y —
14 c.359G>A 外显子4 — — — R120Q D D D D D D — 100
c.476G>C 外显子5 — — — G159A D D D D D D — —
Tab 3 Variants detected in the IVD gene among 11 patients with isovaleric acidemia
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