Biomedical subjects

Hyewon Hahn

Publications and source records attributed to Hyewon Hahn.

8 recordsLinked to original sources

PubMed2006

Two cases of isolated diffuse mesangial sclerosis with WT1 mutations.

Here we report two cases of isolated diffuse mesangial sclerosis (IDMS) with early onset end-stage renal failure. These female patients did not show abnormalities of the gonads or external genitalia. Direct sequencing of WT1 PCR products from genomic DNA identified WT1 mutations in exons 8 (366 Arg>His) and 9 (396 Asp>Tyr). These mutations have been reported previously in association with Denys-Drash syndrome (DDS) with early onset renal failure. Therefore we suggest that, at least in part, IDMS is a variant of DDS and that investigations for the WT1 mutations should be performed in IDMS patients. In cases with identified WT1 mutations, the same attention to tumor development should be required as in DDS patients, and karyotyping and serial abdominal ultrasonograms to evaluate the gonads and kidney are warranted.

Base Sequence↗

PubMed2005

A case of atypical hemolytic uremic syndrome with a transient decrease in complement factor H.

We report a case of sporadic atypical hemolytic uremic syndrome (HUS) with a transient decrease in complement factor H. Referred for hemolysis and azotemia without diarrhea prodrome, this 31-month-old boy showed a decreased complement 3 (C3) and complement factor H (FH) level. However, the factor H gene (HF1) mutation was missing. After the hemolysis was controlled with plasma infusion, the C3 and FH levels recovered. The patient's renal function fully recovered and remained normal, and there was no recurrence of the HUS.

Child, Preschool↗

PubMed2005

Implication of genetic variations in congenital obstructive nephropathy.

The renin-angiotensin system (RAS) has long been implicated in kidney development, and it has been reported that disruption of angiotensin type 2 receptor (AGTR2) results in a wide range of congenital anomalies of the kidney and urinary tract. We investigated the allele frequencies of the AGTR2 and other RAS genes in Korean patients with ureteropelvic junction obstruction, multicystic dysplastic kidney (MCDK), and unilateral renal agenesis (RA). Fifty-three Korean children were enrolled: 37 boys and 16 girls, 27 with hydronephrosis, 23 with MCDK, and 3 with RA. Among 100 healthy Koreans, the frequencies of A and G alleles at the A-G transition site of intron 1 of the AGTR2 gene were 70% (140/200) and 30% (60/200), respectively. In the patient group, the A allele frequency was 57% (60/106) and the G allele frequency was 43% (46/106), significantly higher than in the general population (P=0.024). There was no significant difference of allele frequency between boys and girls. Angiotensin-converting enzyme insertion/deletion, angiotensinogen M235T, and the angiotensin 2 type 1 receptor A1166C genotype distribution showed no difference from those of the control subjects. These findings indicate that the AGTR2 gene may play a major role in the development of congenital obstructive nephropathy.

Angiotensinogen↗

PubMed2004

Age-related differences in adriamycin-induced nephropathy.

We investigated the effects of age on adriamycin-induced nephropathy in mice. Disease was produced by a single intravenous injection of adriamycin (doxorubicin hydrochloride) (AD, 20 mg/kg) in female Balb/C mice of 5 and 12 weeks of age. Urinary protein and transforming growth factor (TGF)-beta1 concentrations were measured and the extent of glomerular sclerosis/hyalinosis and tubulointerstitial fibrosis was scored. Decorin and fibromodulin expression was quantified using reverse transcription-polymerase chain reaction. In normal mouse kidneys, urinary TGF-beta1 excretion and decorin and fibromodulin mRNA did not change with age. When nephropathy was induced, the 12-week-old group demonstrated significantly greater proteinuria, urinary TGF-beta1 excretion, and interstitial fibrosis ( P<0.05) than the 5-week-old group. Decorin and fibromodulin expression was not significantly different between the groups. We conclude that 12-week-old mice develop more severe nephropathy than the younger mice following administration of the equivalent weight-based dose of AD. Decorin and fibromodulin do not play a role in this difference.

Age Factors↗

PubMed2004

Attempted treatment of factor H deficiency by liver transplantation.

Complement factor H (FH) deficiency is one of the causes of atypical hemolytic uremic syndrome (HUS). Most patients with FH deficiency associated HUS progress to end-stage renal disease despite plasma therapy. Moreover, the disease invariably recurs in the graft kidney and causes graft failure. We confirmed FH deficiency in a 30-month-old boy with recurrent HUS of 2 years duration, and attempted an auxiliary partial orthotopic liver transplantation (APOLT) to overcome the sustained intractable dependency on plasma therapy. APOLT restored the plasma FH level, without HUS recurrence, for 7 months. However, thereafter he suffered from serious infectious complications associated with immunosuppression and finally died 11 months after APOLT. In conclusion, although APOLT showed clinical and laboratory improvement for some period in this patient, the final fatal outcome suggests that liver transplantation should be cautiously applied to patients with HUS associated with FH deficiency.

Bacterial Infections↗

PubMed2003

Acute leukemia: an association with atypical hemolytic uremic syndrome.

A 5-year-old boy was admitted for anemia, thrombocytopenia, and azotemia. Bone marrow examination demonstrated only erythroid hyperplasia, and he was diagnosed with an atypical form of hemolytic uremic syndrome (HUS). He was treated with daily prednisolone, and hematological profiles and renal function normalized 1 month later. However, heavy proteinuria persisted, and renal biopsy findings were consistent with HUS. Four months later, pancytopenia developed with recurrence of azotemia, and a second bone marrow examination revealed acute lymphoblastic leukemia (ALL). The remission of proteinuria with no recurrences of HUS after antileukemic treatment suggests that the HUS was associated with the ALL.

Bone Marrow↗

PubMed2003

ATP6B1 gene mutations associated with distal renal tubular acidosis and deafness in a child.

A large proportion of autosomal recessive distal renal tubular acidosis (RTA) is associated with mutations in the ATP6B1 gene encoding the B1 subunit of H+-ATPase. H+-ATPase is one of the key membrane transporters for net acid excretion in the alpha-intercalated cells of the medullary collecting duct. Sensorineural hearing loss frequently accompanies this type of distal RTA. Mutational analysis of the ATP6B1 gene in a 9-year-old Korean boy with distal RTA and sensorineural hearing loss found 2 heterozygous missense point mutations. Although a single case report, this is the second report documenting ATP6B1 mutations in recessive distal RTA with sensorineural hearing loss after the original report by Karet et al and confirms the novelty of these mutations.

Acidosis, Renal Tubular↗

PubMed2002

Reduction of plasma homocysteine by folic acid in children with chronic renal failure.

Hyperhomocysteinemia is a well-known independent risk factor for cardiovascular disease and is a prevalent abnormality in chronic renal failure. However, studies on this abnormality in children with chronic renal failure, before renal replacement therapy, are scarce. In this study, we measured the plasma homocysteine levels of 27 children (mean age 8.9+/-4.8 years) with predialytic chronic renal failure, and analyzed the effect of folic acid supplementation (1 mg daily for 4 weeks) on the homocysteine levels in 14 of these children. The baseline homocysteine concentration of the patients (12.5+/-6.0 micro mol/l) was higher than that of the control group (5.9+/-1.8 micro mol/l, P<0.001), and correlated positively with age and negatively with folic acid concentration. Folic acid and vitamin B(12) concentrations were not below normal in any patient. The homocysteine concentration was decreased from 13.2+/-6.6 micro mol/l (pretreatment) to 9.3+/-4.2 micro mol/l by folic acid supplementation in the 14 patients. Folic acid supplementation also lowered the prevalence of hyperhomocysteinemia from 64.3% to 42.9%. According to these results, we recommend that folic acid supplementation be started in children with chronic renal failure early in the disease course.

Adolescent↗