Horizontal gaze palsy and progressive scoliosis without ROBO3 mutations

Background: To describe clinical and genetic observations in a patient with horizontal gaze palsy and progressive scoliosis (HGPPS) without identified mutations in the ROBO3 gene.

Materials and Methods: Neurologic and orthopedic evaluation of the proband; sequencing all exons, exon-intron boundaries, and promoter region of ROBO3 in the proband and his mother. Array CGH was also carried out in the proband and his mother to evaluate possible chromosomal deletion(s) and/or duplication(s).

Results: The proband had complete horizontal gaze restriction with full vertical gaze and small amplitude horizontal pendular nystagmus. He also had severe scoliosis and brainstem hypoplasia pathognomonic of HGPPS. However, complete sequencing of ROBO3 twice in both forward and reverse directions did not reveal any mutations. Array CGH investigation revealed no chromosomal abnormalities.

Conclusions: This patient had clinical and neuroimaging characteristics considered pathognomonic of HGPPS and yet did not have ROBO3 mutations. A clinical misdiagnosis is unlikely in the absence of facial weakness (typical of Moebius syndrome), deafness (typical of the HOXA1 spectrum), or mental retardation (typical of other central decussation abnormalities). It is perhaps more likely that a phenotype identical to HGPPS can be caused by abnormalities in ROBO3 splice variant expression, by mutations of a gene other than ROBO3, or by some environmental or epigenetic factor(s) inhibiting the action of ROBO3 or its protein product in the developing brainstem.     

Horizontal gaze palsy and progressive scoliosis due to a deleterious mutation in ROBO3

Purpose: To describe a family with horizontal gaze palsy and progressive scoliosis with a deleterious mutation in the ROBO3 gene.

Methods: All family members had full ophthalmologic, neurologic, and orthopedic examinations and complete sequencing of the ROBO3 gene.

Results: Four affected members had complete loss of horizontal gaze with progressive scoliosis that varied between family members. ROBO3 sequencing revealed a novel 15 base deletion (c.2_16 delTGCTGCGCTACCTGC) in exon 1 that segregated in homozygous form with the phenotype and probably alters the shape and ionic charge of the extracellular immunoglobulin motif 1. This mutation was not detected in 100 control chromosomes.

Conclusions: The novel ROBO3 mutation in this family may be among the most deleterious yet reported. Family members in general were severely affected, but comparison of this family to other families with ROBO3 mutations did not yield a definitive phenotype-genotype correlation.     

Synergistic convergence and split pons in horizontal gaze palsy and progressive scoliosis in two sisters

Synergistic convergence is an ocular motor anomaly where on attempted abduction or on attempted horizontal gaze, both the eyes converge. It has been related to peripheral causes such as congenital fibrosis of extraocular muscles (CFEOM), congenital cranial dysinnervation syndrome, ocular misinnervation or rarely central causes like horizontal gaze palsy with progressive scoliosis, brain stem dysplasia. We hereby report the occurrence of synergistic convergence in two sisters. Both of them also had kyphoscoliosis. Magnetic resonance imaging (MRI) brain and spine in both the patients showed signs of brain stem dysplasia (split pons sign) differing in degree (younger sister had more marked changes).     

Horizontal Gaze Palsy with Progressive Scoliosis: A Case Report and Literature Review

Horizontal gaze palsy with progressive scoliosis (HGPPS) is a rare autosomal recessive disorder. The ROBO 3 gene mutation is responsible for the disease. We present a boy aged 12 years who was admitted for scoliosis surgery who had also had horizontal gaze palsy since birth. His brainstem abnormalities were compatible with the syndrome of HGPPS. HGPPS is one of the rare congenital diseases of childhood. Horizontal gaze palsy, ametropia, and progressive scoliosis are the main findings of the disease. This syndrome should be kept in mind for both ophthalmologists and orthopaedic surgeons in patients who present with gaze palsy and scoliosis. Early diagnosis of scoliosis makes it possible to treat the disease at an early stage, and early diagnosis of ametropia is important in the prevention of amblyopia.     

Acquired Convergence Substitution in Horizontal Gaze Palsy and Progressive Scoliosis Associated with ROBO3 Mutations

Two female (aged 12 and 14 years) patients with horizontal gaze palsy and progressive scoliosis (HGPPS) from two different Turkish families were evaluated through ophthalmic, neurological, radiological, and orthopaedic examinations. Each proband had one affected sibling with HGPPS. Both patients had absence of horizontal eye movements and simultaneous adduction of both eyes on attempted horizontal gaze associated with miosis. One proband was observed to have this finding at age 9, which had not been present at 5 years old. Neuroradiological imaging revealed brainstem hypoplasia (split pons sign) and scoliosis. The two index patients harboured different homozygous mutations that were heterozygous in the parents, who are obligate carriers. The emergence of convergence and presence of miosis during lateral gaze suggests that simultaneous adduction occurs as a result of the convergence substitution phenomenon. Substituted convergence in cases with HGPPS may occur with different mechanisms than substituted convergence in cases with pontine lesions.     

Slowly progressive retinitis pigmentosa caused by two novel mutations in the MAK gene

Background: The growing number of clinical trials currently underway for inherited retinal diseases has highlighted the importance of achieving a molecular diagnosis for all new cases presenting to hospital eye services. The male germ cell-associated kinase (MAK) gene encodes a cilium-associated protein selectively expressed in the retina and testis, and has recently been implicated in autosomal recessive retinitis pigmentosa (RP). Whole exome sequencing has previously identified a homozygous Alu insertion in probands with recessive RP and nonsense and missense mutations have also been reported.

Materials and methods: Here we describe two novel mutations in different alleles of the MAK gene in a 75-year-old British female, who had a clinical diagnosis of RP () with onset in the fourth decade and no relevant family history. The mutations were established through next generation sequencing of a panel of 111 genes associated with RP and RP-like phenotypes.

Results: Two novel null mutations were identified within the MAK gene. The first c.1195_1196delAC p.(Thr399fs), was a two base-pair deletion creating a frame-shift in exon 9 predicted to result in nonsense-mediated decay. The second, c.279-2A>G, involved the splice acceptor consensus site upstream of exon 4, predicted to lead to aberrant splicing.

Conclusions: The natural history of this individual’s RP is consistent with previously described MAK mutations, being significantly milder than that associated with other photoreceptor ciliopathies. We suggest inclusion of MAK as part of wider genetic testing in all individuals presenting with RP.     

两个X连锁遗传先天性特发性眼球震颤家系FRMD7基因突变的研究

目的　研究两个Ｘ连锁遗传先天性特发性眼球震颤（ｃｏｎｇｅｎｉｔａｌｉｄｉｏｐａｔｈｉｃｎｙｓｔａｇ-ｍｕｓ,ＣＩＮ）家系的致病基因突变。方法　在获取知情同意后,对两个家系进行病史采集及临床检查以确定其遗传表型;通过系谱分析,确定遗传模式;筛选致病基因进行直接测序,分析发现致病突变。结果　两个家系均为Ｘ连锁遗传,其中ＣＩＮ-０１家系所有患者均携带错义突变ｃ．６８５Ｃ＞Ｔ,位于ＦＲＭＤ７基因外显子８上,该突变可导致ＦＲＭＤ７编码的精氨酸被半胱氨酸替换（ｐ．Ｒ２２９Ｃ）;ＣＩＮ-０２家系所有患者及携带者均携带错义突变ｃ．８８７Ｇ＞Ｃ,位于ＦＲＭＤ７基因外显子９上,该突变使ＦＲＭＤ７蛋白第２９６位的甘氨酸被替换为精氨酸（ｐ．Ｇ２９６Ｒ）。结论　ＦＲＭＤ７基因ｃ．６８５Ｃ＞Ｔ及ｃ．８８７Ｇ＞Ｃ分别是引起ＣＩＮ-０１家系及ＣＩＮ-０２家系致病的主要原因。     

Novel mutations in the BEST1 gene cause distinct retinopathies in two Chinese families

AIM:To describe the clinical heterogeneity of patients with novel mutations in BEST1.METHODS:All the members in the two Chinese families underwent detailed clinical evaluations including best-corrected visual acuity,slit-lamp examination,applanation tonometry,and dilated fundus examination.Fundus autofluorescence,fundus fluorescein angiography,spectral-domain optical coherence tomography,electrooculography,and electroretinogram were also performed.Genomic DNA was extracted from venous blood for all the participants.The targeted next-generation sequencing of inherited retinal disease-associated genes was conducted to identify the causative mutation.RESULTS:A novel BEST1 missense mutation c.41T>C(p.Leu14Ser) was identified in Family 1.It was co-segregated with the phenotype of best vitelliform macular dystrophy(BVMD) and bioinformatics analysis confirmed it was harmful.Another novel BEST1 frameshift mutation c.345₃46insGGCAAGGACG(p.Glu119Glyfs*116) and a novel USH2A missense mutation c.12560G>A,p.Arg4187 His were identified in family 2 with retinitis pigmentosa(RP),which might interact and lead to the phenotype of RP.CONCLUSION:Two novel mutations in the BEST1 gene in two unrelated families with distinct phenotypes and BEST1 mutation accompanied with USH2A mutation would result in RP,which could be enormously helpful in understanding the pathogenesis of the inherited retinal disease caused by a BEST1 mutation.     

Identification of novel mutations of the CHST6 gene in Vietnamese families affected with macular corneal dystrophy in two generations

PURPOSE: To report the clinical and genetic findings of Vietnamese families affected with macular corneal dystrophy (MCD) in 2 generations. METHODS: Two families, including 7 patients and 3 unaffected members, were examined clinically. Blood samples were collected. Fifty normal Vietnamese individuals were used as controls. Genomic DNA was extracted from leukocytes. Analysis of the carbohydrate sulfotransferase (CHST6) gene was performed using polymerase chain reaction and direct sequencing. RESULTS: The typical form of MCD was recognized in family B, in which sequencing of CHST6 gene revealed an nt 1067-1068ins(GGCCGTG) mutation (frameshift after 125V) homozygously in MCD patients and heterozygously in the unaffected members. Family N also showed clinical features of MCD, moderate in the mother but severe in the affected son. Sequencing revealed a single heterozygous Arg211Gln in the mother, compound heterozygous Arg211Gln+ Gln82Stop in the affected son, and heterozygous Arg211Gln mutation in the unaffected members. The identified mutations in these pedigrees were excluded from normal controls. CONCLUSIONS: The novel frameshift and compound heterozygous mutations might be responsible for MCD in the families studied. The phenotypic variation between affected parents and offspring was unclear. In family N, severe MCD phenotype seen in the affected son may be due the fact that he had an early stop codon mutation (Gln82Stop).     

一个中国全色盲家系 CNGB3基因新突变

目的:探讨全色盲一家系的致病基因突变。方法:采用家系调查研究方法,于2018年11月对河南省立眼科医院收集的来自河南省洛阳市的汉族全色盲一家系进行基因测序。详细采集患者的病史资料,对患者及其家系成员进行最佳矫正视力(BCVA)测定,采用裂隙灯显微镜和前置镜检查眼前节和眼底,采用客观和主觉验光法对受检者进行屈光度检查,采...     

两个先天性珊瑚状白内障家系CRYGD基因P23T突变的检测

背景先天性白内障的致病基因及临床表型具有明显的异质性,通过连锁分析进行基因定位,直接测序法筛选致病基因是目前常用的分析方法。目的对2个先天性珊瑚状白内障家系（CCl和CC2）进行致病基因研究。方法收集确诊为常染色体显性遗传的2个先天性珊瑚状白内障家系17名成员的外周静脉血各5ml,包括ll例患者、4名正常成员和2名配偶,提取基因组DNA。选取与已知常染色体显性遗传先天性白内障相关的位点进行基因组扫描,利用微卫星标记物进行PCR扩增并进行序列分析。采用两点法计算LOD值对致病基因进行连锁分析。采用直接测序法对候选致病基因以及3个单核苷酸多态性（sNP）位点（rs2305429,rs2305430,rs2242074）进行序列分析。利用SNP对2个家系的先证者进行单体型分析。结果CCl和CC2家系中的先证者裂隙灯下均可见双眼晶状体核中央混浊区呈珊瑚状,经两点法计算LOD值,家系CCl在微卫星位点D2S325获得的最大LOD值为3．28,而CC2家系在D2S325获得的最大LOD值为1．50,连锁分析结果支持2个家系均与位于2q的候选致病基因CRYGC和CRYGD连锁。基因序列分析发现2个珊瑚状白内障家系均携带CRYGD基因c．C70A．（P．P23T）突变体,而2个家系中的正常人及100名正常对照则无此基因突变。2个家系先证者携带不同类型的单体型结构。结论CRYGD基因C．C70A．（P．P23T）突变是导致2个不同祖先来源的先天性珊瑚状白内障家系CCl和CC2致病的丰要原因。     

GJA3基因在先天性白内障患者中的突变筛查

目的研究缝隙连接蛋白基因GJA3与先天性白内障的关系。方法收集2个先天性白内障家系及30例散发先天性白内障患者,制备外周血白细胞基因组DNA,PCR扩增GJA3基因的外显子及其邻近的内含子,应用SSCP法检测并发现变异条带,将相应的扩增产物回收并纯化后进行GJA3基因测序。测序结果与GenBank公布的GJA3基因正常序列比对找出突变。结果在68例先天性白内障患者中,仅发现1例患者其GJA3基因外显子D段扩增产物SSCP电泳有3条DNA单链带,而其他患者为2条带。将该段序列进行PCR扩增并测序,于编码区未见任何突变,仅在非编码区域发现碱基CA的缺失。结论GJA3基因与本组先天性白内障无关。先天性白内障临床表型与基因型之间的确切关系有待进一步的研究。     

先天性视网膜劈裂症基因突变型与临床表现型的关系

背景研究表明,导致先天性视网膜劈裂症（XLRS）的原因是RS1基因突变,XLRS的不同临床表现型与不同的基因突变类型有关,但基因型与表现型的关系仍不十分清楚。目的研究12个中国人XLRS家系及检测到的11种XLRS!基因突变与临床表现型的关系。方法对12个XLRS家系的28例男性患者（其余3例已死亡）及女性携带者和正常对照者分别进行详细的眼科检查,包括视力、屈光度、裂隙灯及眼底检查,部分患者行全视野视网膜电图（ERG）、眼底血管造影、光学相干断层扫描（OCT）及A／B型超声检查。采用聚合酶链反应（PCR）和单链构象多态性（SSCP）分析,对XLRSl基因突变进行筛查,并对发现异常泳带的PCR产物进行DNA测序,以明确突变位点及突变类型。结果12个家系的28例男性患者中27例有典型的黄斑及视网膜劈裂表现,ERG检查可见b波振幅下降,b／a波比值倒置。12个家系中检出11种不同的XLRSl致病基因突变,其中有4种新发现的基因突变,即：位于外显子1的移码突变（L9CfsX20）;位于外显子5的Aspl45His,Argl56Gly和Trp163X突变,并新发现1种非疾病相关多态性（NSP）,即位于外显子6的576C—T（Pr0192Pro）改变。同时发现位于外显子1的移码突变（22de／T）,外显子1与内含子1剪接位点突变（IVS1＋2TtoC）和Argl02Gln,Arg209His,Arg213Gln突变家系的患者,临床表现为严重型XLRS。结论XLRS1基因突变是导致中国人先天性视网膜劈裂的原因,XLRS的严重临床表现与基因突变的类型及突变位点具有一定的相关性。