The genetic basis of DOORS syndrome: an exome-sequencing study.

Background: Deafness, onychodystrophy, osteodystrophy, mental retardation, and seizures (DOORS) syndrome is a rare autosomal recessive disorder of unknown cause. We aimed to identify the genetic basis of this syndrome by sequencing most coding exons in affected individuals.

Methods: Through a search of available case studies and communication with collaborators, we identified families that included at least one individual with at least three of the five main features of the DOORS syndrome: deafness, onychodystrophy, osteodystrophy, intellectual disability, and seizures.

CDKL5 and ARX mutations in males with early-onset epilepsy.

Mutations in CDKL5 and ARX are known causes of early-onset epilepsy and severe developmental delay in males and females. Although numerous males with ARX mutations associated with various phenotypes have been reported in the literature, the majority of CDKL5 mutations have been identified in females with a phenotype characterized by early-onset epilepsy, severe global developmental delay, absent speech, and stereotypic hand movements. To date, only 10 males with CDKL5 mutations have been reported.

Clinical utility of chromosomal microarray analysis.

Objective: To test the hypothesis that chromosomal microarray analysis frequently diagnoses conditions that require specific medical follow-up and that referring physicians respond appropriately to abnormal test results.

Methods: A total of 46,298 postnatal patients were tested by chromosomal microarray analysis for a variety of indications, most commonly intellectual disability/developmental delay, congenital anomalies, dysmorphic features, and neurobehavioral problems. The frequency of detection of abnormalities associated with actionable clinical features was tallied, and the rate of physician response to a subset of abnormal tests results was monitored.

Characterization of new ACADSB gene sequence mutations and clinical implications in patients with 2-methylbutyrylglycinuria identified by newborn screening.

Short/branched chain acyl-CoA dehydrogenase (SBCAD) deficiency, also known as 2-methylbutyryl-CoA dehydrogenase deficiency, is a recently described autosomal recessive disorder of isoleucine metabolism. Most patients reported thus far have originated from a founder mutation in the Hmong Chinese population. While the first reported patients had severe disease, most of the affected Hmong have remained asymptomatic.

Maternal systemic primary carnitine deficiency uncovered by newborn screening: clinical, biochemical, and molecular aspects.

Background: Systemic primary carnitine deficiency is an autosomal recessive disorder of the carnitine cycle caused by mutations in the SLC22A5 gene that encodes the carnitine transporter, organic cation transporter. Systemic primary carnitine deficiency typically presents in childhood with either metabolic decompensation or cardiomyopathy. We report five families in which low free carnitine levels in the infants' newborn screening have led to the diagnosis of maternal systemic primary carnitine deficiency.

Clinical and mutational spectrum of neurofibromatosis type 1-like syndrome.

Context: Autosomal dominant inactivating sprouty-related EVH1 domain-containing protein 1 (SPRED1) mutations have recently been described in individuals presenting mainly with café au lait macules (CALMs), axillary freckling, and macrocephaly. The extent of the clinical spectrum of this new disorder needs further delineation.

Objective: To determine the frequency, mutational spectrum, and phenotype of neurofibromatosis type 1-like syndrome (NFLS) in a large cohort of patients.

Identification of familial and de novo microduplications of 22q11.21-q11.23 distal to the 22q11.21 microdeletion syndrome region.

Deletions of the 22q11.2 region distal to the 22q11.21 microdeletion syndrome region have recently been described in individuals with mental retardation and congenital anomalies.

Mosaicism for a full mutation, premutation, and deletion of the CGG repeats results in 22% FMRP and elevated FMR1 mRNA levels in a high-functioning fragile X male.

The molecular basis in the majority of fragile X patients results from expansion of the CGG repeats in the FMR1 gene causing its transcriptional silencing and deficiency of its encoded protein FMRP. In this communication, we report on a male patient who lacks the characteristic physical features of fragile X and carries a fully methylated mutation, a premutation, a non-methylated full mutation, and a microdeletion encompassing the entire CGG repeat region and 42 bp of upstream flanking sequence. Southern blot analysis revealed that the methylated full mutation accounted for only 10% of his genotype while the premutation/non-methylated full mutation and the microdeletion constituted 37% and 53%, respectively.

Clinical diagnoses that overlap with choroideremia.

Purpose: To understand which clinical presentations suggest a diagnosis of choroideremia (CHM).

Methods: Retrospective chart review. Included were patients for whom a clinical diagnosis of CHM was suggested, but either protein analysis or direct sequencing of the CHM gene could not confirm the diagnosis.

Dyggve-Melchior-Clausen syndrome: report of seven patients with the Smith-McCort variant and review of the literature.

Dyggve-Melchior-Clausen (DMC) syndrome is a rare autosomal recessive disorder affecting skeletal development. The patients have a striking "barrel-shape" chest, shortened trunk, and various distal deformities, including genu valgum or varum, and minimal decrease in joint mobility. The most notable radiographic findings are a lacy iliac crest apophysis, hip dysplasia, double vertebral hump, and odontoid hypoplasia with atlanto-axial instability.

Mental retardation and abnormal skeletal development (Dyggve-Melchior-Clausen dysplasia) due to mutations in a novel, evolutionarily conserved gene.

Dyggve-Melchior-Clausen dysplasia (DMC) and Smith-McCort dysplasia (SMC) are similar, rare autosomal recessive osteochondrodysplasias. The radiographic features and cartilage histology in DMC and SMC are identical. However, patients with DMC exhibit significant developmental delay and mental retardation, the major features that distinguish the two conditions.

Evidence that Smith-McCort dysplasia and Dyggve-Melchior-Clausen dysplasia are allelic disorders that result from mutations in a gene on chromosome 18q12.

Smith-McCort dysplasia is a rare autosomal recessive osteochondrodysplasia characterized by short limbs and a short trunk with a barrel-shaped chest. The radiographic phenotype includes platyspondyly, generalized abnormalities of the epiphyses and metaphyses, and a distinctive lacy appearance of the iliac crest. We performed a genomewide scan in a consanguineous family from Guam and found evidence of linkage to loci on chromosome 18q12.

Orthopaedic manifestations of Marinesco-Sjögren syndrome.

Two patients with Marinesco-Sjögren syndrome had striking orthopaedic abnormalities that seemed to arise from multiple areas of physeal growth arrest. Major involvement was seen in the distal femora, where bilateral hypoplasia of the lateral condyles resulted in progressive valgus, patellar dislocation, and quadriceps dysfunction. Marinesco-Sjögren syndrome seems to arise from an error in lysosomal handling of lipids.