Department of Pediatric Metabolic Diseases, Children's Hospital, Ankara Bilkent City Hospital, Ankara, Türkiye.
Department of Medical Genetics, Ankara Bilkent City Hospital, Ankara, Türkiye.
J Pediatr Endocrinol Metab. 2024 Feb 6;37(3):271-275. doi: 10.1515/jpem-2023-0481. Print 2024 Mar 25.
The fatty acid 2-hydroxylase gene (FA2H) compound heterozygous or homozygous variants that cause spastic paraplegia type 35 (SPG35) (OMIM # 612319) are autosomal recessive HSPs. gene variants in humans have been shown to be associated with not only SPG35 but also leukodystrophy and neurodegeneration with brain iron accumulation.
A patient with a spastic gait since age seven was admitted to the paediatric metabolism department. She was born to consanguineous, healthy Turkish parents and had no family history of neurological disease. She had normal developmental milestones and was able to walk at 11 months. At age seven, she developed a progressive gait disorder with increased muscle tone in her lower limbs, bilateral ankle clonus and dysdiadochokinesis. She had frequent falls and deteriorating school performance. Despite physiotherapy, her spastic paraplegia was progressive. Whole exome sequencing (WES) identified a homozygous NM_024306.5:c.460C>T missense variant in the gene, of which her parents were heterozygous carriers. A brain MRI showed a slight reduction in the cerebellar volume with no iron deposits.
Pathogenic variants of the gene have been linked to neurodegeneration with iron accumulation in the brain, leukodystrophy and SPG35. When patients developed progressive gait deterioration since early childhood even if not exhibited hypointensity in the basal ganglia detected by neuroimaging, - neurodegeneration with brain iron accumulation should be ruled out. FA2H/SPG35 disease is characterised by notable clinical and imaging variability, as well as phenotypic diversity.
导致痉挛性截瘫 35 型(SPG35)(OMIM#612319)的脂肪酸 2-羟化酶基因(FA2H)复合杂合或纯合变异为常染色体隐性 HSP。人类中的基因变异不仅与 SPG35 有关,还与白质营养不良和伴有脑铁积累的神经退行性变有关。
一名痉挛性步态患者,7 岁时因痉挛性步态而被收入儿科代谢科。她出生于健康的土耳其表亲,无神经病史。她的发育里程碑正常,能在 11 个月大时行走。7 岁时,她出现了进行性步态障碍,下肢肌张力增高,双侧踝阵挛和运动失调。她经常跌倒,学习成绩下降。尽管进行了物理治疗,但她的痉挛性截瘫仍在进展。全外显子组测序(WES)发现了基因中的纯合 NM_024306.5:c.460C>T 错义变异,其父母为杂合携带者。脑 MRI 显示小脑体积略有减小,无铁沉积。
基因的致病性变异与脑铁沉积相关的神经退行性变、白质营养不良和 SPG35 有关。当患者在幼儿时期就出现进行性步态恶化,即使神经影像学未显示基底节低信号时,也应排除脑铁沉积相关的神经退行性变。FA2H/SPG35 疾病的特征是显著的临床和影像学变异性以及表型多样性。