Galloway-Mowat syndrome: a glomerular basement membrane disorder?

Phenotype, genotype, and clinical outcome of Taiwanese with congenital nephrotic syndrome

BACKGROUND/PURPOSE

Congenital nephrotic syndrome (CNS) is one of the important causes of end-stage kidney disease in children. Studies on the genotype, phenotype, and clinical outcome in infants with CNS caused by genetic mutations are scarce.

METHODS

We analyzed the genetic background, clinical manifestations, treatment response, and prognosis of pediatric patients with CNS in Taiwan.

RESULTS

Fifteen infants with CNS were enrolled, and 11 patients of median age 21 (interquartile range 3∼44) days caused by genetic mutations from 10 unrelated families were included in the study. Of the eleven patients, 9 had extra-renal manifestations including microcephaly, facial dysmorphism, and skeletal anomalies. More than two-thirds of the patients had disease onset before 1 month of age. Diffuse meningeal sclerosis was the most common histological characteristic. Whole exome sequencing followed by direct Sanger sequence revealed mutations in OSGEP (R247Q), WT1 (R366H and R467Q), LAMB2 (Q1209∗ and c. 5432-5451 19 bp deletion), NUP93 (D302V), and LAGE3 (c.188+1G > A). Three of the variants were novel. Corticosteroids and/or immunosuppressants were administered in 2 patients, but both were refractory to treatment. During the mean 3.5 years of follow-up, all but two died of uremia and sepsis. The two survivors reached end-stage kidney disease and required peritoneal dialysis, and one of them underwent uneventful renal transplantation.

CONCLUSION

The majority of patients with CNS in Taiwan were caused by OSGEP followed by WT1 mutation. R247Q is the hotspot mutation of OSGEP in Taiwan. CNS patients in Taiwan suffer from significant morbidity and mortality.

Galloway-Mowat syndrome in Taiwan: OSGEP mutation and unique clinical phenotype

Background

Galloway-Mowat syndrome (GAMOS) is a rare autosomal recessive disease characterized by the combination of glomerulopathy with early-onset nephrotic syndrome and microcephaly with central nervous system anomalies. Given its clinical heterogeneity, GAMOS is believed to be a genetically heterogenous group of disorders. Recently, it has been reported that mutations in KEOPS-encoding genes, including the OSGEP gene, were responsible for GAMOS.

Results

Overall, 6 patients from 5 different Taiwanese families were included in our study; the patients had an identical OSGEP gene mutation (c.740G > A transition) and all exhibited a uniform clinical phenotype with early-onset nephrotic syndrome, craniofacial and skeletal dysmorphism, primary microcephaly with pachygyria, and death before 2 years of age. We reviewed their clinical manifestations, the prenatal and postnatal presentations and ultrasound findings, results of imaging studies, associated anomalies, and outcome on follow-up. All individuals were found to have an “aged face” comprising peculiar facial dysmorphisms. Arachnodactyly or camptodactyly were noted in all patients. Neurological findings consisted of microcephaly, hypotonia, developmental delay, and seizures. Brain imaging studies all showed pachygyria and hypomyelination. All patients developed early-onset nephrotic syndrome. The proteinuria was steroid-resistant and eventually resulted in renal function impairment. Prenatal ultrasound findings included microcephaly, intrauterine growth restriction, and oligohydramnios. Fetal MRI in 2 patients confirmed the gyral and myelin abnormalities.

Conclusions

Our study suggests that a careful review of the facial features can provide useful clues for an early and accurate diagnosis. Prenatal ultrasound findings, fetal MRI, genetic counseling, and mutation analysis may be useful for an early prenatal diagnosis.

Collapsing Glomerulopathy in a Child with Galloway-Mowat Syndrome

Galloway-Mowat syndrome (GMS) is an autosomal recessive disorder with a poor prognosis that was first defined as a triad of central nervous system involvement, hiatal hernia, and nephrotic syndrome. However, this syndrome is now known to have a heterogeneous clinical presentation. The nephrotic syndrome is steroid resistant and is responsible for the outcome. The combination of collapsing glomerulopathy and GMS is very rare. A 26-month-old boy presented with steroid-resistant nephrotic syndrome associated with neurologic findings, including microcephaly, psychomotor retardation, and nystagmus. Magnetic resonance imaging showed marked cerebral atrophy, optic atrophy, and hypomyelination. A renal biopsy was consistent with collapsing glomerulopathy. If collapsing glomerulopathy is associated with neurological abnormalities, especially with microcephaly, clinicians should consider GMS as a possible underlying cause.

Infantile nephrotic syndrome with microcephaly and global developmental delay: the Galloway Mowat Syndrome

The authors present the first case of Galloway Mowat Syndrome (GMS), a rare disorder comprising of nephrotic syndrome in association with microcephaly, from India. An 11-mo-old girl with microcephaly, developmental delay and nystagmus presented with nephrotic syndrome. The perinatal and neonatal periods had been uneventful. The renal biopsy revealed mesangial proliferation with IgM deposition, while MRI of the brain showed hypomyelination. Molecular diagnosis by polymerase chain reaction (PCR) did not reveal any pathogenic sequences in the exons and the flanking intronic regions of the NPHS2 gene and LAMB2 gene. The infant responded to prednisolone. GMS must be suspected whenever microcephaly and global developmental delay occurs in association with nephrotic syndrome, as this is important for prognostication and genetic counseling. The genetics of GMS remains an enigma and further research is required to delineate the pathogenesis of this disorder.

Neuropathological homology in true Galloway-Mowat syndrome

Galloway-Mowat syndrome is a rare condition that is likely hereditary though the underlying offending gene has not been identified, and is characterized by microcephaly and severe nephrotic syndrome culminating in childhood death. Some of the reported cases have abnormalities in neuronal migration and intractable seizures, but many of the described cases focus on the renal pathology and emphasize a diversity of clinical and pathological features. The case described herein includes a thorough neuropathological description, and when the neuroradiology and neuropathology of the previously published cases is scrutinized, a fairly consistent clinical and neuropathological phenotype emerges.

Analysis of genes encoding laminin beta2 and related proteins in patients with Galloway-Mowat syndrome

Galloway-Mowat syndrome (GMS) is a rare autosomal recessive disorder characterized by early onset nephrotic syndrome and microcephaly with various anomalies of the central nervous system. GMS likely represents a heterogeneous group of disorders with hitherto unknown genetic etiology. The clinical phenotype to some extent overlaps that of Pierson syndrome (PS), which comprises congenital nephrotic syndrome and distinct ocular abnormalities but which may also include neurodevelopmental deficits and microcephaly. PS is caused by mutations of LAMB2, the gene encoding laminin beta2. We hypothesized that GMS might be allelic to PS or be caused by defects in proteins that interact with laminin beta2. In a cohort of 18 patients with GMS or a GMS-like phenotype we therefore analyzed the genes encoding laminin beta2 (LAMB2), laminin alpha5 (LAMA5), alpha3-integrin (ITGA3), beta1-integrin (ITGB1) and alpha-actinin-4 (ACTN4), but we failed to find causative mutations in these genes. We inferred that LAMA5, ITGA3, ITGB1, and ACTN4 are not directly involved in the pathogenesis of GMS. We excluded LAMB2 as a candidate gene for GMS. Further studies are required, including linkage analysis in families with GMS to identify genes underlying this disease.

Late-onset growth restriction in Galloway-Mowat syndrome: a case report

Galloway-Mowat syndrome (GMS) is a rare autosomal recessive disorder and is characterized by marked intrauterine growth retardation, central nervous system anomalies, and early onset nephrotic syndrome. Of the reported cases in the literature, all were diagnosed postnatally. We describe a case of GMS in which only late-onset intrauterine growth restriction was detected by prenatal ultrasound. In her fourth pregnancy, the mother had delivered a male baby with clinical features of GMS who died at seven months of age due to early onset of nephrotic syndrome. In her fifth pregnancy, serial ultrasound examinations were normal during the first and second trimester of pregnancy. Growth restriction and microcephaly were not detectable until 28 to 32 weeks' gestation. At 40 weeks' gestation, a female baby was born with dysmorphic features of GMS. Nephrotic syndrome developed after birth and renal biopsy revealed minimal change nephrotic syndrome. The prenatal course of this case suggests GMS may not be diagnosed in early pregnancy and the only abnormality detected before birth was intrauterine growth restriction.

Microcephaly, cerebellar atrophy, and focal segmental glomerulosclerosis in two brothers: a possible mild form of Galloway-Mowat syndrome

We report two brothers with microcephaly, cerebellar atrophy, and focal segmental glomerulosclerosis. The elderbrother showed nephrotic syndrome from 2 years of age and died of renal failure at 8 years of age. The younger brother showed mild proteinuria from 2 years of age, and his renal function was still preserved at 15 years of age. We propose that our patients may be affected with a mild form of Galloway-Mowat syndrome or another autosomal recessive syndrome with focal segmental glomerulosclerosis and central nervous system abnormalities.