척수성 근위축증 환자의 유전형과 표현형에 대한 상관관계 연구

원선영(Seon-Young Won),유경화(Kyong-Hwa Ryu),이은하(Eun-Ha Lee),한시훈(Si-Houn Hahn),배기수(Ki-Soo Pai),김성환(Sung-Hwan Kim) 대한소아신경학회 1999 대한소아신경학회지 Vol.7 No.1

배 경 : 척수성근위축증(SMA)은 척수 전각세포나 뇌간핵의 변성 또는 소실로 인해 점진적 인 근력의 약화나 근위축을 초래하는 질환으로 상염색체상에서 열성 유전되는 소아 신경근질환이다. 이 질환은 염색체 5번 장완(5q11.2-13.3)에 존재하는 여러 candidate gene, 즉 SMN, NAIP 및 p44 유전자의 결함으로 발생되는 것으로 본다. Candidate 유전자들의 분자적 특징이 증명되었음에도 불구하고, 유전양상과 임상양상과의 상관관계는 아직 불분명한 상태이다. 유전자의 결손과 같이 유전자 conversion도 중요한 기작으로 부각되고 있으며, 유전양상과 임상양상과의 상관관계에 대한 연구에는 많은 어려움들이 나타나고 있다. 목 적 : 한국인 척수성 근위축증 환자에서 SMN, NAIP 및 p44 유전자의 척수성 근위축증 표현형에 미치는 영향을 관찰하여 유전적인 양상과 표현형 사이의 상관관계를 규명하고, 유전자의 결손뿐만 아니라 유전자의 conversion이 질환 발현에 중요한 기전이 될 수 있음을 규명하고자 하였다. 또한 이 연구에서는 정상 신생아에서의 유전자의 rearrangement의 빈도를 조사하였다. 방 법 : 척수성 근위축증에 영향을 주는 candidate 유전자인 SMN 유전자의 exon 7과 exon 8, NAIP 유전자의 exon 5와 p44 유전자 5'말단의 C15l유전자의 결손을 확인하기 위해 각각의 primer을 이용하여 PCR 증폭을 하였으며, PCR 산물들을 각각 DraⅠ, DdeⅠ, Alu의 제한효소를 처리하여, 결손 여부를 관찰하였다. 또한, p44 유전자의 3'말단의 N1839부위는 SSCP로 분석하였다. 결 과 : 1) 제 1형 환자 8명과 제 2형 환자 2명에 대한 조사에서 제 1형 환자 5명에서 SMN 유전자 뿐만 아니라, NAIP와 p44 유전자의 결손을 관찰하였고 나머지 제 1형의 3명과 제 2형 모두에서는 SMN 유전자만이 결손 되어 있었다. 2) 본 연구 대상아 100명에서 SMN와 NAIP 유전자의 결손 여부를 관찰한 결과 NAIP 유전자는 모두 존재하였으나, centromeric SMN 유전자가 2%정도에서 결손 되어 있음을 확인하였다. 3) SMN, NAIP 및 p44 유전자 모두 결손을 보이는 제 1형 환자 중 telomeric exon 8만이 존재하는 환아 1명에서 telomeric exon 7이 centromeric exon 7로 유전자 conversion이 발생된 것을 확인하였다. 결론 : 척수성 근위축증 중 제 1형에서만 candidate 유전자인 SMN, NAIP 및 p44 유전자의 결손이 발견되어 이 세 가지 유전자 모두의 결손이 임상적으로 심한 양상과 관련이 높은 것으로 추정되나 SMN 유전자만 결손된 경우도 제 1형과 제 2형 모두에서 발견되어 SMN 유전자결손 외에 또 다른 요소가 임상양상에 영향을 주는 것으로 추정된다. 한 명의 제 1형 환자에서 관찰된 centromeric SMN 유전자의 telomeric 위치로의 gene conversion은 SMN 유전자 copy수와 임상양상간의 상관관계가 불분명함을 제시하고 있다. 정상아에서 관찰된 높은 빈도의 유전자 rearrangement는 산전진단시 주의를 필요로 하는 것으로 생각된다. Background : Spinal muscular atrophy(SMA) is the second most common disease with autosomal recessive mode of inheritance in children and characterized by degeneration of anterior horn cells of the spinal cord resulting in weakness and wasting of voluntary muscles. This disease is caused by deletion of many candidate genes including SMN, p44, NAIP on chromosome 5q11.2-13.3. Although molecular characteristics of candidate genes were identified, genotype-phenotype correlation has not been clearly elucidated yet. Nevertheless, gene conversion, previously described as simply as gene deletion, appears to be very important mechanism as a molecular pathogenesis, and even makes more difficult to pursue the correlation. Purpose : This study was aimed to define the correlation between genotype and phenotype of SMA in Korean patients. The significance of SMN gene as well as NAIP gene, p44 gene in the progress of disease process and phenotypic correlation with gene conversion was evaluated. This study was also undertaken to determine the frequency of gene rearrangements in normal population. Method : Eight type Ⅰ SMA patients and two type Ⅱ SMA patients were studied. SMN, NAIP, and p44 gene deletion were analysed by PCR amplification and restriction enzyme digestion with DraⅠ, DdeⅠ and AluⅠ, respectively. p44 gene was also analyzed by SSCP. Gene conversion was defined by centromeric and telomeric SMN gene exon 7 to exon 8 PCR amplification followed by DdeⅠ restiction enzyme digestion. Result : 1) Five of eight type Ⅰ patients showed deletion of SMN, NAIP and p44 gene, while the rest of type Ⅰ and all type Ⅱ patients showed deletion of SMN gene only. 2) We examined SMN and NAIP gene deletion on 100 normal newborns, which showed the deletion of centromeric SMN gene in two newborns, the relative frequency of 2% in gene rearrangement. 3) There was one case of type Ⅰ SMA showing deletion of telomeric SMN exon 7 but not SMN axon 8 suggestive of gene conversion occurred during the recombination as a molecular pathogenesis. Conclusion : The major deletion of SMA candidate genes, SMN, NAIP, and p44 gene appear to be involved in severe phenotype since these three candidate genes deletion were noted only in type 1 cases. However, SMN gene deletion only identified both in type 1 and type 2 explains that SMN gene may plan an major role in the pathogenesis of SMA and also suggests that other factors may be affecting the severity in spinal muscular atrophy. One patient with type Ⅰ which showed the conversion of the centromeric SMN gene to the teleomeric gene strongly supports that SMN gene copy number may not be correlated with the severity in SMA. Our molecular findings suggest that phenotype is not clearly correlated with genotype. Prenatal screening should be carefully undertaken to interpretate because of high frequency of gene rearrangements in normal populations.

발달 지연으로 내원한 Cystathionine 뇨증 1례

변소훈(So Hoon Byun),이희선(Hee Sun Lee),피대훈(Dae Hun Pee),이기형(Kee Hyoung Lee),은백린(Baik-Lin Eun),한시훈(Si Houn Hahn) 대한소아신경학회 2003 대한소아신경학회지 Vol.11 No.1

γ-cystathionase 결핍으로 인해 생긴 cystathioninuria는 상염색체 열성 유전질환으로, 다양한 임상양상을 보이며, 이 질환에 특징적으로 연관된 임상양상은 없는 것으로 추측되며, 다수에서 pyridoxine 경구 투여에 의해 호전된다. 저자들은 발달 지연을 주소로 내원하여 소변 아미노산 분석 검사 결과 시스틴뇨증으로 진단되고 pyridoxine 경구 투여로 호전된 1례를 경험하고, 우리나라에서 첫 증례라고 사료되어 이에 문헌 고찰과 함께 보고하는 바이다. Cystathionine is well-known intermediate in the metabolism of methionine. It is cleaved to cysteine and homoserine by γ-cystathionase. This enzyme utilize pyridoxal 5'-phosphate as coenzyme. γ-cystathionase deficiency leads to persistent excretion of large amount of cystathionine in urine, as well as to accumulation of cystathionine in body tissues and fluids. It is inherited as an autosomal recessive trait and shows wide variety of clinical manifestations. No clinical abnormality seems to be specifically associated with γ-cystathionase deficiency. The majority of patients responded to high dose administration of pyridoxine. We report the first case of cystathioninuric patient in Korea, 19 months of female with developmental delay. In brain MRI, there was generalized mild brain atrophy. There were several times of brief paroxysmal generalized polyspike and wave discharges in electroencephalography(EEG). In amino acid analysis of urine, there was elevated level of cystathionine. She was treated with high dose of pyridoxine. In follow up analysis of urinary amino acid, the cystathionine level was markedly decreased to normal range, and EEG was normalized. Her development shows improvement.

Kinky Hair 질환 1례

이영섭(Young Sup Lee),박석원(Seok Won Park),차병호(Byung Ho Cha),임백근(Baek Keun Lim),김종수(Jong Soo Kim),이원수(Won Soo Lee),김동진(Dong Jin Kim),김명순(Myung Soon Kim),조규남(Kyou Nam Cho),한시훈(Si Houn Hahn ) 대한소아신경학회 2001 대한소아신경학회지 Vol.9 No.1

저자들은 전신성 강직경련 및 발육지경, 호흡곤란으로 입원하여 추적관찰 중이던 15개월 남아에서 낮은 혈청 구리농도와 ceruloplasmin 농도를 보이며 전형적인 임상증상과 ATP7A의 Exon 19에서 점돌연변이를 보인 특징적인 Kinky hair 질환 1례를 경험하였기에 보고하는 바이다. Kinky hair disease is X-lined recessive neurodegenerative disorder produced by defects in a gene(ATP7A) that encodes an intracellular copper-transporting ATPase. About 90-95% of the patients have a severe clinical course leading to death in early childhood. ATP7A mutations associated with Menkes disease show great variety from cytogenetic abnormalities to partial gene deletions to single base-pair changes. We experienced a 15 month old boy with loss of developmental milestones, hypotonia, seizures and failure to thrive. On laboratory findings, the levels of serum copper and ceruloplasmin were low. Electron microscopy of hair illustrated pathognomic pili torti and other abnormalities such as trichorrhexis nodosa and trichoptilosis(longitudinal splitting of the shaft). Brain magnetic resonance image showed diffuse cerebral and cerebellar atrophy with tortousity of cerebral blood vessels. Genetic defect was evaluated. Our sequencing data on the amplified exon 19 of ATP7ase genomic DNA confirmed point mutation, G1255A, resulting in a glycine-to-arginine conversion. So, we report a brief view with the related literatures.

구리대사의 분자생물학적 발전 : 윌슨병의 새로운 이해

한시훈 대한간학회 1998 Clinical and Molecular Hepatology(대한간학회지) Vol.4 No.3

빈혈을 동반한 급성감염성 질환에서의 혈청 Ferritin치와 혈색소 변동에 대한 연구

韓始薰,崔平和,金舜謙 최신의학사 1989 最新醫學 Vol.32 No.5

아급성형 Gaucher 씨 병

김현수,한시훈,김효철,김현주,신석균 대한내과학회 1996 대한내과학회지 Vol.50 No.2

Gaucher's disease is an inherited metabolic disorder characterized by enzyme defect, cerebroside β-glucosidase and accumulation of glucocerebroside in reticuloendothelial system. There are three subtypes of Gaucher's disease. Type 1(non-neuronopathic) is the chronic form occurring rather frequently and shows hepatosplenomegaly, pancytopenia and bone lesion. Type 2(acute neuronopathic) is uniform in se- verity and progression, showing acute neurologic deterioration and early death. Type 3(subacute neuronopathic) is less rapidly progressive than type 1 disease, but is also a neurovisceral storage disorder. The diagnosis is confirmed by assay of glucocerebrosidase in white cells or fibroblasts. With enzyme assay, however, carrier and subtype determination is unreliable. But it is possible that studies of the gene for glucocerebrosidase and its mutation may lead to more definitive determination. The treatment is divided into two modalities, the first is symptomatic management with splenectomy, the second is enzyme replacement, allogeneic bone marrow transplantation and somatic cell gene transfer. The second modalities are currently experimental. Recently, two sisters of subacute neuronopathic Gaucher's disease who presented with pancytopenia, hepatosplenomegaly and seizure disorder, were diagnosed as type III Gaucher's disease and confirmed by the enzyme assay. Here we reported these cases with literature review.