Abstract：
Population diversity is important and rare disease isolates can frequently reveal novel homozygous or biallelic mutations that lead to expanded clinical heterogeneity, with diverse clinical presentations.
The present study describes two consanguineous families with a total of seven affected individuals suffering from a clinically similar severe syndromic neurological disorder, with abnormal development and central nervous system (CNS) and peripheral nervous system (PNS) abnormalities. Whole exome sequencing (WES) and Sanger sequencing followed by 3D protein modeling was performed to identify the disease-causing gene. RNA was extracted from the fresh blood of both families affected and healthy individuals.
The families were clinically assessed in the field in different regions of Khyber Pakhtunkhwa. Magnetic resonance imagining was obtained in the probands and blood was collected for DNA extraction and WES was performed. Sanger sequencing confirmed a homozygous, likely pathogenic mutation (GRCh38: chr17:42684199G>C; (NM_003632.3): c.333G>C);(NP_003623.1): p.(Trp111Cys) in the CNTNAP1 gene in family A, previously associated with Congenital Hypo myelinating Neuropathy 3 (CHN3; OMIM # 618186) and a novel nonsense variant in family B, (GRCh38: chr16: 57654086C>T; NC_000016.10 (NM_001370440.1): c.721C>T); (NP_001357369.1): p.(Gln241Ter) in the ADGRG1 gene previously associated with bilateral frontoparietal polymicrogyria (OMIM # 606854); both families have extended CNS and PNS clinical manifestations. In addition, 3D protein modeling was performed for the missense variant, p.(Trp111Cys), identified in the CNTNAP1, suggesting extensive secondary structure changes that might lead to improper function or downstream signaling. No RNA expression was observed in both families affected and healthy individuals hence showing that these genes are not expressed in blood.
In the present study, two novel biallelic variants in the CNTNAP1 and ADGRG1 genes in two different consanguineous families with a clinical overlap in the phenotype were identified. Thus, the clinical and mutation spectrum is expanded to provide further evidence that CNTNAP1 and ADGRG1 are very important for widespread neurological development.
The present study describes two consanguineous families with a total of seven affected individuals suffering from a clinically similar severe syndromic neurological disorder, with abnormal development and central nervous system (CNS) and peripheral nervous system (PNS) abnormalities. Whole exome sequencing (WES) and Sanger sequencing followed by 3D protein modeling was performed to identify the disease-causing gene. RNA was extracted from the fresh blood of both families affected and healthy individuals.
The families were clinically assessed in the field in different regions of Khyber Pakhtunkhwa. Magnetic resonance imagining was obtained in the probands and blood was collected for DNA extraction and WES was performed. Sanger sequencing confirmed a homozygous, likely pathogenic mutation (GRCh38: chr17:42684199G>C; (NM_003632.3): c.333G>C);(NP_003623.1): p.(Trp111Cys) in the CNTNAP1 gene in family A, previously associated with Congenital Hypo myelinating Neuropathy 3 (CHN3; OMIM # 618186) and a novel nonsense variant in family B, (GRCh38: chr16: 57654086C>T; NC_000016.10 (NM_001370440.1): c.721C>T); (NP_001357369.1): p.(Gln241Ter) in the ADGRG1 gene previously associated with bilateral frontoparietal polymicrogyria (OMIM # 606854); both families have extended CNS and PNS clinical manifestations. In addition, 3D protein modeling was performed for the missense variant, p.(Trp111Cys), identified in the CNTNAP1, suggesting extensive secondary structure changes that might lead to improper function or downstream signaling. No RNA expression was observed in both families affected and healthy individuals hence showing that these genes are not expressed in blood.
In the present study, two novel biallelic variants in the CNTNAP1 and ADGRG1 genes in two different consanguineous families with a clinical overlap in the phenotype were identified. Thus, the clinical and mutation spectrum is expanded to provide further evidence that CNTNAP1 and ADGRG1 are very important for widespread neurological development.
摘要：
背景：群体多样性很重要，罕见的疾病分离株可以经常揭示新的纯合或双等位基因突变，从而导致扩大的临床异质性，不同的临床表现。
方法：本研究描述了两个近亲家庭，共有七个受影响的个体患有临床上相似的严重综合征神经系统疾病，伴有发育异常和中枢神经系统（CNS）和周围神经系统（PNS）异常。进行全外显子组测序（WES）和Sanger测序，然后进行3D蛋白质建模以鉴定致病基因。RNA是从受影响的家庭和健康个体的新鲜血液中提取的。
结果：在开伯尔-普赫图赫瓦省不同地区对这些家庭进行了临床评估。在先证者中获得磁共振成像，收集血液进行DNA提取并进行WES。Sanger测序证实纯合，可能的致病突变（GRCh38：chr17：42684199G>C；（NM_003632.3）：c.333G>C）；（NP_003623.1）：家族A中CNTNAP1基因中的p。（Trp111Cys），先前与先天性髓鞘减少神经病3（CHN3;OMIM#618186）和家族B中的一个新的无义变体有关，（GRCh38：chr16：57654086C>T；NC_000016.10（NM_001370440.1）：c.721C>T）；（NP_001357369.1）：ADGRG1基因中的p。（Gln241Ter）先前与双侧额叶顶多基因（OMIM＃606854）相关；两个家族都有扩展的CNS和PNS临床表现。此外,对错义变体进行了3D蛋白质建模，p.（Trp111Cys），在CNTNAP1中鉴定，提示广泛的二级结构变化，可能导致不正确的功能或下游信号传导。在受影响的家庭和健康个体中均未观察到RNA表达,因此表明这些基因在血液中不表达。
结论：在本研究中，在两个不同的近亲家族的CNTNAP1和ADGRG1基因中鉴定出两个新的双等位基因变异体,其表型具有临床重叠.因此，扩大了临床和突变谱,进一步证明CNTNAP1和ADGRG1对广泛的神经系统发育非常重要.
方法：本研究描述了两个近亲家庭，共有七个受影响的个体患有临床上相似的严重综合征神经系统疾病，伴有发育异常和中枢神经系统（CNS）和周围神经系统（PNS）异常。进行全外显子组测序（WES）和Sanger测序，然后进行3D蛋白质建模以鉴定致病基因。RNA是从受影响的家庭和健康个体的新鲜血液中提取的。
结果：在开伯尔-普赫图赫瓦省不同地区对这些家庭进行了临床评估。在先证者中获得磁共振成像，收集血液进行DNA提取并进行WES。Sanger测序证实纯合，可能的致病突变（GRCh38：chr17：42684199G>C；（NM_003632.3）：c.333G>C）；（NP_003623.1）：家族A中CNTNAP1基因中的p。（Trp111Cys），先前与先天性髓鞘减少神经病3（CHN3;OMIM#618186）和家族B中的一个新的无义变体有关，（GRCh38：chr16：57654086C>T；NC_000016.10（NM_001370440.1）：c.721C>T）；（NP_001357369.1）：ADGRG1基因中的p。（Gln241Ter）先前与双侧额叶顶多基因（OMIM＃606854）相关；两个家族都有扩展的CNS和PNS临床表现。此外,对错义变体进行了3D蛋白质建模，p.（Trp111Cys），在CNTNAP1中鉴定，提示广泛的二级结构变化，可能导致不正确的功能或下游信号传导。在受影响的家庭和健康个体中均未观察到RNA表达,因此表明这些基因在血液中不表达。
结论：在本研究中，在两个不同的近亲家族的CNTNAP1和ADGRG1基因中鉴定出两个新的双等位基因变异体,其表型具有临床重叠.因此，扩大了临床和突变谱,进一步证明CNTNAP1和ADGRG1对广泛的神经系统发育非常重要.
