Molecular analysis of KAL-1 in a series of Kallmann syndrome and normosmic idiopathic hypogonadotropic hypogonadism patients from Northwestern China

We conducted an analysis of the Kallmann syndrome 1 （KAL-1） genotype in 17 patients with Kallmann syndrome （KS）, 9 patients with normosmic idiopathic hypogonadotropic hypogonadism （nlHH） and 20 age-matched normal men in Northwestern China. To do this, we used multiplex PCR analysis with exon-flanking primers and automated sequencing techniques with peripheral blood DNA samples. Intragenic deletions were found at the KAL-1 locus in two KS patients. One case with an atrial septal defect exhibited an intragenic deletion of exon 6. Another KS patient with cryptorchidism had intragenic deletions of exons 5 and 6. For the nlHH patients, no abnormalities were observed in the exonic and flanking sequences of KAL-1. This report describes two intragenic deletions of KAL-1 in two KS patients and suggests that KAL-1 deletion might be more prevalent in KS patients with other congenital organ abnormalities than those described previously in other series from Northwestern China.     

Aminoaciduria and glycosuria following severe childhood lead poisoning

To determine the incidence of renal functional abnormalities after lead poisoning, we evaluated the parameters of renal tubular function in 134 children and young adults, 8–13 years after chelation therapy for severe lead poisoning. There was no evidence of hypertension or reduced kidney function as assessed by serum creatinine (Cr) concentrations. Urinary α-amino nitrogen (U_aan) concentrations were significantly increased compared with 19 healthy age-matched controls. Ninety-four children (70%) had aminoaciduria (U_aan/Cr >0.23). Urinary glucose excretion was also significantly higher than that of 2 historical controls. Thirty-two children (24%) had glycosuria (>125 mg/24 h). Fractional excretion of phosphate was normal in all children. We conclude that a partial Fanconi syndrome can persist up to 13 years after childhood lead poisoning. Received August 11, 1997; received in revised form November 20, 1997; accepted November 21, 1997     

Novel homozygous deletion of segmental KAL1 and entire STS cause Kallmann syndrome and X‐linked ichthyosis in a Chinese family

Kallmann syndrome (KS) is a genetically heterogeneous disease characterised by hypogonadotrophic hypogonadism in association with anosmia or hyposmia. This condition affects 1 in 10 000 men and 1 in 50 000 women. Defects in seventeen genes including KAL1 gene contribute to the molecular basis of KS. We report the clinical characteristics, molecular causes and treatment outcome of two Chinese brothers with KS and X‐linked ichthyosis. The phenotypes of the patients were characterised by bilateral cryptorchidism, unilateral renal agenesis in one patient but normal kidney development in another. The patients had low serum testosterone, follicle‐stimulating hormone and luteinising hormone levels and a blunt response to the gonadotrophin‐releasing hormone stimulation test. After human chorionic gonadotrophin treatment, the serum testosterone levels were normalized, and the pubic hair, penis length and testicular volumes were greatly improved in both of the patients. The two affected siblings had the same novel deletion at Xp22.3 including exons 9‐14 of KAL1 gene and entire STS gene. Our study broadens the mutation spectrum in the KAL1 gene associated with KS and facilitates the genetic diagnosis and counselling for KS.     

Respiratory complications during anaesthesia in Apert syndrome

BACKGROUND: Clinical experience with anaesthesia for a series of patients with Apert syndrome (craniosynostosis, midface hypoplasia and syndactyly) has not been reported previously. METHODS: In this review, 10 years of experience was examined at our hospital. There were 145 anaesthetics administered to 18 individuals. RESULTS: There were 16 complications (15 were perioperative wheezing) which occurred in seven patients. In four cases, surgery was cancelled due to intractable wheezing. CONCLUSIONS: We could not demonstrate any benefit from preoperative administration of nebulized albuterol. Paediatric anaesthetists should be aware of this high incidence of respiratory complications in Apert syndrome.     

Glutathione depletion and increased apoptosis rate in human cystinotic proximal tubular cells

We have determined levels of glutathione (GSH), ATP, mitochondrial complex activity and apoptosis rate in proximal tubular cells (PTCs) exfoliated from urine in cystinotic (n=9) and control (n=9) children. Intracellular GSH was significantly depleted in cystinotic PTCs compared with controls (6.8 nmol GSH/mg protein vs 11.8 nmol GSH/mg protein; P<0.001), but there were no significant differences in mitochondrial complex activities or ATP levels under basal conditions. Cystinotic PTCs showed significantly increased apoptosis rate. After PTCs had been stressed by hypoxia, there was further depletion of GSH in cystinotic and control PTCs (2.4 nmol GSH/mg protein vs 7.2 nmol GSH/mg protein; P<0.001). Hypoxic stress led to increased complex I and complex IV activities in control but not in cystinotic PTCs. ATP levels were significantly reduced in cystinotic PTCs after hypoxic stress (12.2 nmol/mg protein vs 26.9 nmol/mg protein; P<0.001). GSH depletion occurs in this in vitro model of cystinotic PTCs, is exaggerated by hypoxic stress and may contribute to reduced ATP and failure to increase complex I/IV activities. Apoptotic rate is also increased, and these mechanisms may contribute to cellular dysfunction in cultured, human cystinotic PTCs.     

Exfoliated human proximal tubular cells: a model of cystinosis and Fanconi syndrome

The renal Fanconi syndrome (FS) is characterised by generalised proximal tubular dysfunction. Cystinosis is the most common genetic cause of the FS and results from defective function of cystinosin, due to mutations of the CTNS gene leading to intralysosomal cystine accumulation. Despite these advances in our understanding of the molecular basis of cystinosis, the mechanisms of proximal tubular cell (PTC) dysfunction are still unknown. We have further characterised an in vitro model of cultured cells exfoliated in patients urine. We cultured cells from 9 cystinosis children, 4 children with Lowe syndrome and 8 controls. PTC phenotype and homogeneity were studied by lectin staining, immunocytochemistry (using ZO-1 as an epithelial marker) and enzyme cytochemistry (using -glutamyltransferase as a PTC marker). All cultured cells showed PTC phenotype. Cystinosin was stained using anti-cystinosin antibody and co-localised to the lysosomes with LAMP-2 antibody. Additionally, we have demonstrated significantly elevated intracellular cystine levels in cystinotic cell lines (13.8±2.3 nmol 1/2 cystine/mg protein, P <0.001) compared with controls. We believe this in vitro model will allow further investigation of cystinosis and other types of the FS.     

Early sonographic aspects of kidney morphology in Bardet-Biedl syndrome

Bardet-Biedl syndrome is an autosomal recessive disorder characterized by postaxial hexadactyly, obesity, mental retardation, pigmented retinopathy, hypogonadism, and renal disease. Morphological changes are present in all areas of the kidney, the renal medulla being the most frequently affected site. Cystic and dysplastic changes are prevalent. Seven children from five families were followed from birth through their 5th birthday. Serial renal sonography revealed a number of characteristic features. Bilateral renal enlargement and increased parenchymal echogenicity were present at birth. The usual corticomedullary differentiation was absent. Pyramids were either not seen or deformed. With high-resolution ultrasonography, small cysts were detected at the corticomedullary junction. After the 3rd month of life, there was a striking inversion of normal echogenicity, the inner medulla became more echogenic and was demarcated from the less-echogenic cortex. After 12 months, the kidney size regressed significantly. Fetal lobulation persisted in some patients. In conclusion, ultrasonography is a useful tool to evaluate the extent of renal lesions, but more importantly to differentiate bilateral polycystic kidney diseases in the newborn period. Received January 10, 1997; received in revised form January 8, 1998; accepted January 9, 1998     

Bilateral congenital multicystic dysplasia of the kidney

The clinical and pathological features of congenital multicystic dysplasia of the kidney are reviewed and we report of a patient with bilateral dysplasia who lived longer than do most such patients. When multicystic disease of the kidney is bilateral, it is commonly confused with polycystic disease. Despite the fatal prognosis, differentiation is essential for appropriate genetic counselling since multicystic disease is not a familial occurrence.     

Molecular diagnosis of kidney transplant failure based on urine

In light of the organ shortage, there is a great responsibility to assess postmortal organs for which procurement has been consented and to increase the life span of transplanted organs. The former responsibility has moved many centers to accept extended criteria organs. The latter responsibility requires an exact diagnosis and, if possible, omission of the harmful influence on the transplant. We report the course of a kidney transplant that showed a steady decline of function over a decade, displaying numerous cysts of different sizes. Clinical workup excluded the most frequent causes of chronic transplant failure. The filed allocation documents mentioned the donor’s disease of oral‐facial‐digital syndrome, a rare ciliopathy, which can also affect the kidney. Molecular diagnosis was performed by culturing donor tubular cells from the recipient´s urine more than 10 years after transplantation. Next‐generation panel sequencing with DNA from tubular urinary cells revealed a novel truncating mutation in OFD1, which sufficiently explains the features of the kidney transplants, also found in the second kidney allograft. Despite this severe donor disease, lifesaving transplantation with good long‐term outcome was enabled for 5 recipients.     

The study of abnormal bone development in the Apert syndrome Fgfr2+/S252W mouse using a 3D hydrogel culture model

Apert syndrome is caused by mutations in fibroblast growth factor receptor 2 (Fgfr2) and is characterized by craniosynostosis and other skeletal abnormalities. The Apert syndrome Fgfr2+/S252W mouse model exhibits perinatal lethality. A 3D hydrogel culture model, derived from tissue engineering strategies, was used to extend the study of the effect of the Fgfr2+/S252W mutation in differentiating osteoblasts postnatally. We isolated cells from the long bones of Apert Fgfr2+/S252W mice (n=6) and cells from the wild-type sibling mice (n=6) to be used as controls. During monolayer expansion, Fgfr2+/S252W cells demonstrated increased proliferation and ALP activity, as well as altered responses of these cellular functions in the presence of FGF ligands with different binding specificity (FGF2 or FGF10). To better mimic the in vivo disease development scenario, cells were also encapsulated in 3D hydrogels and their phenotype in 3D in vitro culture was compared to that of in vivo tissue specimens. After 4 weeks in 3D culture in osteogenic medium, Fgfr2+/S252W cells expressed 2.8-fold more collagen type I and 3.3-fold more osteocalcin than did wild-type controls (p<0.01). Meanwhile, Fgfr2+/S252W cells showed decreased bone matrix remodeling and expressed 87% less Metalloprotease-13 and 71% less Noggin (p<0.01). The S252W mutation also led to significantly higher production of collagen type I and II in 3D as shown by immunofluorescence staining. In situ hybridization and alizarin red S staining of postnatal day 0 (P0) mouse limb sections demonstrated significantly higher levels of osteopontin expression and mineralization in Fgfr2+/S252W mice. Complementary to in vivo findings, this 3D hydrogel culture system provides an effective in vitro venue to study the pathogenesis of Apert syndrome caused by the analogous mutation in humans.     

Hydronephrotic obstructed kidney mimicking a congenital multicystic kidney: Case report with review of literature

Objective: To report a case of obstructed hydronephrotic kidney mimicking a multicystic kidney and to review the literature regarding differentiation of the hydronephrotic variant of multicystic kidney from the obstructed hydronephronic kidney. To suggest a possible algorithm in distinguishing them.Methods:We have reported a case of a 35-year-old male who presented with dull aching pain and a palpable right-sided cystic flank mass of several years duration. The initial workup suggested a nonfunctioning multicystic kidney while the operative findings and histopathology were suggestive of an obstructed hydroenphrotic kidney with pyelonephritic changes. We searched the literature using the key words hydronephrotic dysplastic kidney and multicystic kidney.Results:A detailed literature search did not reveal any such publication describing the differentiation of the hydronephrotic multicystic dysplastic kidney from the obstructed hydronephrotic kidney of pelviureteral obstruction. We reviewed the existing literature on this subject, on the basis of which, we have suggested a six-stepladder approach to distinguish such cases.Conclusion:By using the 6 step ladder protocol algorithm suggested by us one can attempt to distinguish the hydronephrotic variant of multicystic dysplastic kidney from the hydronephrotic kidney due to pelviureteral obstruction in patients presenting with a symptomatic cystic flank masses of renal origin. Differentiation between the two may be difficult at times due to the medial/central placement of cysts in the former. This is necessary since renal salvage may be possible in the latter while timely nephrectomy may be considered in the former to prevent against the hazards of leaving behind a dysplastic kidney in situ.     

Glypicans and the biology of renal malformations

The molecular mechanisms that control renal development are largely undefined. The discovery of mutations in the gene encoding glypican-3 (Gpc3) in humans with Simpson-Golabi-Behmel syndrome (SGBS) and renal dysplasia, and the establishment of a genetic mouse model of GPC3 deficiency has provided an opportunity to define the role of GPC3 during renal development. Glypicans are a family of cell surface heparan sulfate proteoglycans that control growth factor signalling in nonrenal tissues. Mutational inactivation of Gpc3 causes somatic overgrowth and cystic renal dysplasia, as observed in SGBS. Overgrowth of the ureteric bud and its branches and increased ureteric bud cell proliferation is observed during the early stages of renal development. Subsequently, during corticomedullary differentiation, cortical collecting duct cell proliferation is increased, while medullary collecting duct cells proliferate at a reduced rate and undergo apoptosis resulting in degeneration of the medulla. However, cells that constitute medullary cysts are characterized by enhanced cell proliferation and a lower rate of apoptosis. Thus, the phenotype arising from Gpc3 inactivation demonstrates that tight regulation of cell proliferation and apoptosis is critical during formation of the renal medulla. Received: 27 April 2000 / Revised: 20 June 2000 / Accepted: 20 July 2000