Myopathic mtDNA Depletion Syndrome Due to Mutation in TK2 Gene.

Whole-exome sequencing was used to identify the disease gene(s) in a Spanish girl with failure to thrive, muscle weakness, mild facial weakness, elevated creatine kinase, deficiency of mitochondrial complex III and depletion of mtDNA. With whole-exome sequencing data, it was possible to get the whole mtDNA sequencing and discard any pathogenic variant in this genome. The analysis of whole exome uncovered a homozygous pathogenic mutation in thymidine kinase 2 gene ( TK2; NM_004614.

Clinical and molecular characterization of five Spanish kindreds with X-linked adrenal hypoplasia congenita: atypical findings and a novel mutation in NR0B1.

Background: X-linked adrenal hypoplasia congenita (AHC) is caused by NR0B1 (DAX1) gene mutations. Affected male children suffer from adrenal insufficiency, leading to a salt-wasting crisis in early infancy and hypogonadotropic hypogonadism in adulthood.

Objective: To characterize clinically and at the molecular level a cohort of Spanish patients with AHC.

Delineation of the clinically recognizable 17q22 contiguous gene deletion syndrome in a patient carrying the smallest microdeletion known to date.

We describe a patient with a 1.34 Mb microdeletion at chromosome band 17q22, which is also present in his affected mother. To better delineate this microdeletion syndrome, we compare the clinical and molecular characteristics of 10 previously reported cases and our patient.

Mutations in PRPS1 causing syndromic or nonsyndromic hearing impairment: intrafamilial phenotypic variation complicates genetic counseling.

Background: PRPS1 encodes isoform I of phosphoribosylpyrophosphate synthetase (PRS-I), a key enzyme in nucleotide biosynthesis. Different missense mutations in PRPS1 cause a variety of disorders that include PRS-I superactivity, nonsyndromic sensorineural hearing impairment, Charcot-Marie-Tooth disease, and Arts syndrome. It has been proposed that each mutation would result in a specific phenotype, depending on its effects on the structure and function of the enzyme.

Exome sequencing identifies a novel mutation in PIK3R1 as the cause of SHORT syndrome.

Background: SHORT syndrome is a rare autosomal dominant condition whose name is the acronym of short stature, hyperextensibility of joints, ocular depression, Rieger anomaly and teething delay (MIM 269880). Additionally, the patients usually present a low birth weight and height, lipodystrophy, delayed bone age, hernias, low body mass index and a progeroid appearance.

Case Presentation: In this study, we used whole-exome sequencing approaches in two patients with clinical features of SHORT syndrome.