Dataset Information

In vivo expression of putative LMX1B targets in nail-patella syndrome kidneys.

ABSTRACT: The nail-patella syndrome (NPS) is characterized by nail and bone abnormalities, associated with glomerular involvement in approximately 40% of patients. Typical glomerular changes consist of fibrillar material in the irregularly thickened glomerular basement membrane. NPS is inherited as an autosomal dominant trait and caused by heterozygous loss of function mutations in LMX1B, a member of the LIM homeodomain protein family. Mice with homozygous inactivation of the gene exhibit nail and skeletal defects, similar to those observed in patients, associated with glomerular abnormalities. Strong reduction in the glomerular expression of the alpha3 and alpha4 chains of type IV collagen, and of podocin and CD2AP, two podocyte proteins critical for glomerular function, has been observed in Lmx1b null mice. The expression of these proteins appeared to be regulated by Lmx1b. To determine whether these changes in podocyte gene expression are involved in the development of NPS nephropathy, using immunohistological techniques, we analyzed the podocyte phenotype and the renal distribution of type IV collagen chains in the kidneys of seven NPS patients with severe glomerular disease. We also examined the nature of the fibrillar material present within the glomerular extracellular matrix. The glomerular basement membrane fibrillar material was specifically labeled with anti-type III collagen antibodies, suggesting a possible regulation of type III collagen expression by LMX1B. The expression of the alpha3 and alpha4 chains of type IV collagen, and of podocin and CD2AP, was found to be normal in the seven patients. These findings indicate that heterozygous mutations of LMX1B do not appear to dramatically affect the expression of type IV collagen chains, podocin, or CD2AP in NPS patients.

SUBMITTER: Heidet L

PROVIDER: S-EPMC1868155 | biostudies-literature | 2003 Jul

REPOSITORIES: biostudies-literature

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In vivo expression of putative LMX1B targets in nail-patella syndrome kidneys.

Heidet Laurence L Bongers Ernie M H F EM Sich Mireille M Zhang Shao-Yu SY Loirat Chantal C Meyrier Alain A Broyer Michel M Landthaler Gérard G Faller Bernadette B Sado Yoshikazu Y Knoers Nine V A M NV Gubler Marie-Claire MC

The American journal of pathology 20030701 1

The nail-patella syndrome (NPS) is characterized by nail and bone abnormalities, associated with glomerular involvement in approximately 40% of patients. Typical glomerular changes consist of fibrillar material in the irregularly thickened glomerular basement membrane. NPS is inherited as an autosomal dominant trait and caused by heterozygous loss of function mutations in LMX1B, a member of the LIM homeodomain protein family. Mice with homozygous inactivation of the gene exhibit nail and skeleta ...[more]

PMID: 12819019

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Project description:PurposeTo report the clinical, ophthalmic, extraophthalmic, and genetic characteristics of nail-patella syndrome (NPS) in a Chilean family and to investigate the expressivity of open angle glaucoma (OAG) and ocular hypertension (OHT) in the family members.MethodsFive family members affected with NPS and two unaffected members underwent a complete ophthalmologic examination, including computerized visual field, optical coherence tomography (OCT) of the optic disc and ultrasound pachymetry. Renal function was assessed by urinalysis and blood tests. Orthopedic evaluations were also performed, including radiological studies of the wrist, elbow and hip joints. Genomic DNA was extracted from peripheral leukocytes of the five affected and two unaffected family members. Exons 2-6 of the LIM homeobox transcription factor 1-beta (LMX1B) gene were screened for mutations by DNA sequencing of the proband. We also screened for mutations in exon 2 by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) of the other participants and 91 blood donors.ResultsFive living family members from three generations were positively diagnosed with NPS, three of them with varying degrees of OAG and one with OHT. Retinal nerve fiber layer (RNFL) thickness measured by spectral domain OCT was below normal values in three individuals. All subjects evaluated had normal nephrologic function. Orthopedic, clinical, and radiological alterations were compatible with NPS. Screening for mutations in exons 2- 6 of LMX1B showed a heterozygous missense mutation c.194 A>C changing glutamine to proline within exon 2 in codon 65 (Q65P) of the coding sequence. This mutation was present in all NPS subjects and absent in the unaffected family members and in 91 Chilean blood donors.ConclusionsThis is the first report of c.194 A>C mutation in LMX1B in a Chilean family with NPS and the second worldwide. The phenotype associated with this mutation is variable within the family, although we noted a close connection between the presence of the c.194 A>C mutation and the presence of OHT or OAG and probably also with an early onset of OHT in patients with NPS. All subjects older than 21 years had either OHT or OAG. We also suggest that the LMX1B mutation may be related to affective disorders.

Dataset Information

In vivo expression of putative LMX1B targets in nail-patella syndrome kidneys.

Publications

In vivo expression of putative LMX1B targets in nail-patella syndrome kidneys.

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