A Case Report of Nail-Patella Syndrome / 罕见病研究

Nail-patella syndrome (NPS) is a hereditary rare disease that can involve fingernail, patella, elbow, and iliac bones. In this article, we report a case of a girl-9 and 1 quarter years old who had asthmatic contractures in both elbows, thumbnail hypoplasia in both hands, patellar dislocation of both knees, iliac angle protrusion of both sides, and scoliosis. Whole exome sequencing suggests the presence of a LMX1B NM_002316.4:c.706G > C(p.Ala236Pro) mutation. NPS is an autosomal dominant disease associated with gene mutation of LMX1B, which can be diagnosed by combining the patient′s clinical manifestations and genetic results. The treatment now only targets on symptoms, relieving the localized severe lesion but not cure right now.

LMX1B-associated disease presented with prominent asymptomatic proteinuria / 中华实用儿科临床杂志

Objective:To analyze clinical data of 3 children with LMX1B-associated disease characterized by asymptomatic glomerular proteinuria, thus improving the recognition of asymptomatic proteinuria with genetic causes. Methods:Three patients with LMX1B-associated disease presented with prominent asymptomatic proteinuria diagnosed by the next-generation sequencing in Department of Pediatrics, Peking University First Hospital from April 2014 to October 2017 were included in this study.Clinical data, including renal and extrarenal manifestations, renal biopsy, and family history, were collected and retrospectively analyzed. Results:All 3 children were girls, the age of onset were 2 years, 1 year, and 4 years, respectively, and the diagnosis age were 11 years, 5 years and 6 years, respectively.All of them had glomerular proteinuria, and nephrotic-level proteinuria occurred in one patient.Microscopic hematuria was found in 2 patients.All of them had normal renal function.Only one patient underwent renal biopsy.Electron microscopy of the first time of biopsy revealed segmental thinning of the glomerular basement membrane.Re-biopsy 4 years later showed irregular thickening of the glomerular basement membrane, moth-eaten appearance and collagen fibrillar material deposition.No abnormalities of nails, limbs and joints were observed by physical examination.Two patients had a family history of renal disease.Conclusions:Genetic factors should be considered in children with obscure onset asymptomatic proteinuria without definite clinical causes.Genetic testing can help diagnose and guide treatment as early as possible.

Enhancement of Aggression Induced by Isolation Rearing is Associated with a Lack of Central Serotonin / 神经科学通报·英文版

Isolation rearing (IR) enhances aggressive behavior, and the central serotonin (5-hydroxytryptamine, 5-HT) system has been linked to IR-induced aggression. However, whether the alteration of central serotonin is the cause or consequence of enhanced aggression is still unknown. In the present study, using mice deficient in central serotonin Tph2 and Lmx1b, we examined the association between central serotonin and aggression with or without social isolation. We demonstrated that central serotonergic neurons are critical for the enhanced aggression after IR. 5-HT depletion in wild-type mice increased aggression. On the other hand, application of 5-HT in Lmx1b mice inhibited the enhancement of aggression under social isolation conditions. Dopamine was downregulated in Lmx1b mice. Similar to 5-HT, L-DOPA decreased aggression in Lmx1b mice. Our results link the serotoninergic system directly to aggression and this may have clinical implications for aggression-related human conditions.

A Synonymous Genetic Alteration of LMX1B in a Family with Nail-Patella Syndrome

The gene responsible for nail-patella syndrome, LMX1B, has recently been identified on chromosome 9q. Here we present a patient with nail-patella syndrome and an autosomal dominant pattern of inheritance. A 17-year-old girl visited our clinic for the evaluation and treatment of proteinuria. She had dystrophic nails, palpable iliac horns, and hypoplastic patellae. Electron microscopy of a renal biopsy showed irregular thickening of the glomerular basement membrane. A family history over three generations revealed five affected family members. Genetic analysis found a change of TCG to TCC, resulting in a synonymous alteration at codon 219 in exon 4 of the LMX1B gene in two affected family members. The same alteration was not detected in an unaffected family member. This is the first report of familial nail-patella syndrome associated with an LMX1B in Korea mutation, However, we can not completely rule out the possibility that the G-to-C change may be a single nucleotide polymorphism as this genetic mutation cause no alteration in amino acid sequence of LMX1B.

Clinico-Genetic Study of Nail-Patella Syndrome

Nail-patella syndrome (NPS) is an autosomal dominant disease that typically involves the nails, knees, elbows and the presence of iliac horns. In addition, some patients develop glomerulopathy or adult-onset glaucoma. NPS is caused by lossof- function mutations in the LMX1B gene. In this study, phenotype-genotype correlation was analyzed in 9 unrelated Korean children with NPS and their affected family members. The probands included 5 boy and 4 girls who were confirmed to have NPS, as well as 6 of their affected parents. All of the patients (100%) had dysplastic nails, while 13 patients (86.7%) had patellar anomalies, 8 (53.3%) had iliac horns, 6 (40.0%) had elbow contracture, and 4 (26.7%) had nephropathy including one patient who developed end-stage renal disease at age 4.2. The genetic study revealed 8 different LMX1B mutations (5 missense mutations, 1 frame-shifting deletion and 2 abnormal splicing mutations), 6 of which were novel. Genotype-phenotype correlation was not identified, but inter- and intrafamilial phenotypic variability was observed. Overall, these findings are similar to the results of previously conducted studies, and the mechanism underlying the phenotypic variations and predisposing factors of the development and progression of nephropathy in NPS patients are still unknown.