Genome-wide association and whole exome sequencing studies reveal a novel candidate locus for restless legs syndrome

INTRODUCTION

The restless legs syndrome (RLS) is a common heritable neurologic disorder which is characterized by an irresistible desire to move and unpleasant sensations in the legs.

METHODS

We aim to identify new variants associated with RLS by performing genome-wide linkage and subsequent association analysis of forty member's family with history of RLS.

RESULTS

We found evidence of linkage for three loci 7q21.11 (HLOD = 3.02), 7q21.13-7q21.3 (HLOD = 3.02) and 7q22.3 (HLOD = 3.09). Fine-mapping of those regions in association study using exome sequencing identified SEMA3A (p-value = 8.5·10^-4), PPP1R9A (p-value = 7.2·10^-4), PUS7 (p-value = 8.7·10^-4), CDHR3 (p-value = 7.2·10^-4), HBP1 (p-value = 1.5·10^-4) and COG5 (p-value = 1.5·10^-4) genes with p-values below significance threshold.

CONCLUSION

Linkage analysis with subsequent association study of exome variants identified six new genes associated with RLS mapped on 7q21 and q22.

OCULOECTODERMAL SYNDROME: A NEW CASE WITH GIANT CELL GRANULOMAS AND NON-OSSIFYING FIBROMAS

Oculoectodermal syndrome (OES) is a very rare disorder with an unknown etiology and characterized by aplasia cutis congenita, epibulbar dermoid and hyperpigmentation areas on the skin. To the best of our knowledge, two cases of OES have been reported to date with recurrent giant cell granuloma in the jaw and one of them also had a non-ossified fibroma in the long bones. Herein, we report the second case with aplasia cutis congenita, epibulbar dermoid, hyperpigmentation along Blaschko lines and also giant cell granuloma in the jaw and non-ossified fibromas in the bones.

Spondylocostal dysostosis associated with type I split cord malformation and double nipple on one side: a case report

Jarcho Levin syndrome is a rare genetic disorder characterized by multipl vertebral and costal anomalies at birth. Jarcho Levin syndrome includes two phenotypic groups: spondylothoracic dysostosis and spondylocostal dysostosis. The prognosis of spondylothoracic dysostosis has worse than spondylocostal dysostosis, because of respiratory complications. Associated malformations include those of the congenital heart disease, urogenital malformation, skeletal anomalies and neural tube defects. We present a patient with spondylocostal dysostosis, who also had type I split cord malformation, tethered cord, scoliosis and double nipple on the right. Although the association of spondylocostal dysostosis and type I split cord malformation is very rare, double nipples on one side is no previously reported.

A patient with 9q subtelomeric deletion syndrome with additional findings

We describe a one-year old girl, with a de novo segmental aneusomy due to the subtelomeric deletion of the long arm of chromosome 9, determined via fluorescence in situ hybridization technique. Common clinical findings of the 9q subtelomeric deletion syndrome are developmental delay, hypotonia, microcephaly and dysmorphic facial features especially including midface hypoplasia and low set ears. Sensorineural deafness, as a rare condition of the syndrome is also announced. Presented case with sensorineural deafness has most of the common clinical findings of the syndrome, except brachycephaly, downslanting palpebral fissures, synophrys, epicanthus and low set ears, and has also additional findings like microtia, asymmetric and simple ears, long curly eyelashes and fetal finger pads which are not reported previously.

Linkage analysis and a novel COL4A5 mutation in a large Turkish family with Alport syndrome

BACKGROUND

Alport syndrome (AS) is a renal disease that is characterized by proteinuria and progressive renal failure, and often accompanied by sensorineural hearing loss and ocular changes. Mutations in the genes encoding for three members of the type IV collagen protein family have been found to be the cause of the disease. We describe a large Turkish family with X-linked AS. We performed linkage analysis in this family and sequencing to identify the mutation in the proband whose disease was confirmed by renal biopsy.

METHODS

After genomic DNAs extracted, linkage to the COL4A5 locus was examined using the 2B6 and 2B20, DXS1106, DXS1105 and COL4A5 markers. In addition, COL4A5 gene sequence analysis was performed in the proband.

RESULTS

Genetic linkage analysis demonstrated co-segregation of the disease. Haplotype analysis showed that the same haplotype was carried by all affected males and obligatory carrier females. Mutation analysis of the proband has revealed a novel nonsense mutation (c.1135C>T; Gln379X) in exon 19 of the COL4A5 gene which may lead to a more severe phenotype in affected family members carrying this mutation. According to GenBank data base, this mutation has not been reported previously.

CONCLUSION

Genetic testing identified a previously undescribed COL4A5 mutation as the cause of the disease.