Angiotensin II receptor blocker induced fetopathy: 7 cases

BACKGROUND

During a period of 12 months 7 newborns with a partially severe fetopathy caused most probably by maternal sartan-intake in pregnancy were treated in 5 German teaching hospitals. Sartans antagonize the effect of angiotensin II at the AT1-receptor and are used to treat arterial hypertension.

METHOD

We presented 2 cases at the yearly GNPI meeting 2010 and we were informed about similar cases in other German teaching hospitals which we brought together in this publication.

RESULTS

In the presented cases, maternal sartan intake was noticed at different times in pregnancy and was in part discontinued some weeks before delivery. In all pregnancies oligohydramnios was present and fetal kidneys displayed a hyperechogenic structure on ultrasound. The newborns' postnatal course varied: oligohydramnios sequence with lung hypoplasia, arterial hypotension and renal insufficiency were the predominant problems of the first days of life. The majority (4/7) of infants did not survive this period, in other cases there was a complete (1/7) recovery of renal function whereas others survived with renal impairment (2/7), in part requiring chronic dialysis. Further distinctive features seen frequently were disturbances of cranial ossification and flaccid paralysis of hands and feet with deviations as well as sensorineural hearing loss.

CONCLUSION

These case reports again underline the hazardousness of maternal sartan intake with potential fatal outcome for the newborn. Though the use of sartans in pregnancy is contraindicated and several case reports of sartan induced fetopathies exist, the risk of sartan treatment generally seems to be underestimated.

Influence of peptidylarginine deiminase type 4 genotype and shared epitope on clinical characteristics and autoantibody profile of rheumatoid arthritis

BACKGROUND

Recent evidence suggests that distinction of subsets of rheumatoid arthritis (RA) depending on anti-cyclic citrullinated peptide antibody (anti-CCP) status may be helpful in distinguishing distinct aetiopathologies and in predicting the course of disease. HLA-DRB1 shared epitope (SE) and peptidylarginine deiminase type 4 (PADI4) genotype, both of which have been implicated in anti-CCP generation, are assumed to be associated with RA.

OBJECTIVES

To elucidate whether PADI4 affects the clinical characteristics of RA, and whether it would modulate the effect of anti-CCPs on clinical course. The combined effect of SE and PADI4 on autoantibody profile was also analysed.

METHODS

373 patients with RA were studied. SE, padi4_94C>T, rheumatoid factor, anti-CCPs and antinuclear antibodies (ANAs) were determined. Disease severity was characterised by cumulative therapy intensity classified into ordinal categories (CTI-1 to CTI-3) and by Steinbrocker score.

RESULTS

CTI was significantly associated with disease duration, erosive disease, disease activity score (DAS) 28 and anti-CCPs. The association of anti-CCPs with CTI was considerably influenced by padi4_94C>T genotype (C/C: OR(adj) = 0.93, p(adj) = 0.92; C/T: OR(adj) = 2.92, p(adj) = 0.093; T/T: OR(adj) = 15.3, p(adj) = 0.002). Carriage of padi4_94T exhibited a significant trend towards higher Steinbrocker scores in univariate and multivariate analyses. An association of padi4_94C>T with ANAs was observed, with noteworthy differences depending on SE status (SE-: OR(adj) = 6.20, p(adj)<0.04; SE+: OR(adj) = 0.36, p(adj) = 0.02) and significant heterogeneity between the two SE strata (p = 0.006).

CONCLUSIONS

PADI4 genotype in combination with anti-CCPs and SE modulates clinical and serological characteristics of RA.

[13C2]oxalate absorption in children with idiopathic calcium oxalate urolithiasis or primary hyperoxaluria

Intestinal oxalate absorption is an important part of oxalate metabolism influencing its urinary excretion and its measurement can be a valuable diagnostic tool in hyperoxaluric disorders. In this study, we use [(13)C(2)]oxalate absorption under standardized dietary conditions to assess intestinal oxalate absorption and its impact on urinary oxalate excretion. Tests were conducted in age-matched pediatric patients that included 60 with idiopathic calcium oxalate urolithiasis, 13 with primary hyperoxaluria, and 35 healthy children. In the idiopathic stone formers, median oxalate absorption was significantly higher than that in the controls or in patients with primary disease. From standardized values obtained in control patients, oxalate hyperabsorption was detected in 23 patients with idiopathic disease but not in any patients with primary hyperoxaluria; therefore, a significant correlation between intestinal absorption and urinary excretion was found only in those with the idiopathic disease. We have shown that increased intestinal oxalate absorption is an important risk factor of idiopathic calcium oxalate urolithiasis. In contrast, low intestinal oxalate absorption in patients with primary hyperoxaluria indicates that only foods with excessive oxalate content be restricted from their diet.

The Uromodulin C744G mutation causes MCKD2 and FJHN in children and adults and may be due to a possible founder effect

Autosomal dominant medullary cystic kidney disease type 2 (MCKD2) is a tubulo-in terstitial nephropathy that causes renal salt wasting, hyperuricemia, gout, and end-stage renal failure in the fifth decade of life. This disorder was described to have an age of onset between the age of 20-30 years or even later. Mutations in the Uromodulin (UMOD) gene were published in patients with familial juvenile hyperuricemic nephropathy (FJHN) and MCKD2. Clinical data and blood samples of 16 affected individuals from 11 different kindreds were collected. Mutational analysis of the UMOD gene was performed by exon polymerase chain reaction (PCR) and direct sequencing. We found the heterozygous C744G (Cys248Trp) mutation, which was originally published by our group, in an additional four kindreds from Europe and Turkey. Age of onset ranged from 3 years to 39 years. The phenotype showed a variety of symptoms such as urinary concentration defect, vesicoureteral reflux, urinary tract infections, hyperuricemia, hypertension, proteinuria, and renal hypoplasia. Haplotype analysis showed cosegragation with the phenotype in all eight affected individuals indicating that the C744G mutation may be due to a founder effect. Moreover, we describe a novel T229G (Cys77Gly) mutation in two affecteds of one kindred. Three of the affected individuals were younger than 10 years at the onset of MCKD2/FJHN. Symptoms include recurrent urinary tract infections compatible with the published phenotype of the Umod knockout mouse model. This emphasizes that MCKD2 is not just a disease of the young adult but is also relevant for children.

Is there a genotype-phenotype correlation in primary hyperoxaluria type 1?

There is ongoing debate about a genotype-phenotype correlation in patients with primary hyperoxaluria type 1 and specific AGXT mutations. However, other determinants like environmental factors or modifer genes may play a pivotal role in the heterogeneity of the disease. The report of Lorenzo and co-workers highlights this situation, presenting data of a whole population with just one specific AGXT mutation.

Oxalobacter formigenes: a potential tool for the treatment of primary hyperoxaluria type 1

Primary hyperoxaluria is characterized by severe urolithiasis, nephrocalcinosis, and early renal failure. As treatment options are scarce, we aimed for a new therapeutic tool using colonic degradation of endogenous oxalate by Oxalobactor formigenes. Oxalobacter was orally administered for 4 weeks as frozen paste (IxOC-2) or as enteric-coated capsules (IxOC-3). Nine patients (five with normal renal function, one after liver-kidney transplantation, and three with renal failure) completed the IxOC-2 study. Seven patients (six with normal renal function and one after liver-kidney transplantation) completed the IxOC-3 study. Urinary oxalate or plasma oxalate in renal failure was determined at baseline, weekly during treatment and for a 2-week follow-up. The patients who showed >20% reduction both at the end of weeks 3 and 4 were considered as responders. Under IxOC-2, three out of five patients with normal renal function showed a 22-48% reduction of urinary oxalate. In addition, two renal failure patients experienced a significant reduction in plasma oxalate and amelioration of clinical symptoms. Under IxOC-3 treatment, four out of six patients with normal renal function responded with a reduction of urinary oxalate ranging from 38.5 to 92%. Although all subjects under IxOC-2 and 4 patients under IxOC-3 showed detectable levels of O. formigenes in stool during treatment, fecal recovery dropped directly at follow up, indicating only transient gastrointestinal-tract colonization. The preliminary data indicate that O. formigenes is safe, leads to a significant reduction of either urinary or plasma oxalate, and is a potential new treatment option for primary hyperoxaluria.

Deletion of Lys224 in regulatory domain 4 of Factor H reveals a novel pathomechanism for dense deposit disease (MPGN II)

We report a novel pathomechanism for membranoproliferative glomerulonephritis type II (MPGN II) caused by a mutant Factor H protein expressed in the plasma. Genetic analyses of two patients revealed deletion of a single Lys residue (K224) located within the complement regulatory region in domain 4 of Factor H. This deletion resulted in defective complement control: mutant protein purified from the plasma of patients showed severely reduced cofactor and decay-accelerating activity, as well as reduced binding to the central complement component C3b. However, cell-binding activity of the mutant protein was normal and comparable to wild-type Factor H. The patients are daughters of consanguineous parents. As both patients but also their healthy mother were positive for C3 nephritic factor, the mutant Factor H protein is considered relevant for unrestricted activation of the disease-causing activation of the alternative complement pathway. Replacement of functional Factor H by fresh frozen plasma (10-15 ml/kg/14 days) was well tolerated, prevented so far disease progression in both patients, and is in the long run expected to preserve kidney function.

Successful Renal Transplantation in a Child With Thrombosis of the Inferior Vena Cava and Both Iliac Veins

An 8-year-old girl who was born premature in the 24th gestational week suffered a septic venous thrombosis due to an indwelling central line during the early perinatal period. As a result the inferior vena cava including the intrahepatic segment and both iliac veins was obliterated. The right kidney was primarily dysplastic, and the left kidney developed a partial infarction. Renal function was compensated until the age of 6 years. Magnetic resonance angiography at that time showed a collateral system via the azygos vein. The venous pressure and its variation with breathing as measured invasively showed normal values. During pretransplant initiation of immunosuppressive therapy, the child developed cerebral convulsions after the third dose of cyclosporine. Therefore we utilized a regimen of rapamycin, mycophenolate mofetil, and steroids. The transplantation was performed using a living donor graft from the child's mother. The relatively long vein from the left kidney was used for anastomosis with a large presacral collateral vein. Twelve months after transplantation the kidney function is stable with a serum creatinine of 0.5 mg/dL. The recipient thrombosis of the caval and iliac veins is not a principal contraindication for successful renal transplantation. MR angiography and invasive pressure measurements facilitated evaluation of the collateral venous system. The living donation setting allowed the initiation of an immunosuppressive regimen that was tailored to the concomitant diseases of the child.