A homozygous 1-base pair deletion in the arrestin gene is a frequent cause of Oguchi disease in Japanese

Oguchi disease is a rare autosomal recessive form of congenital stationary night blindness with all other visual functions, including visual acuity, visual field, and colour vision being usually normal. A typical clinical feature of the disorder is a golden or gray-white discolouration of the fundus which disappears in the dark-adapted state and reappears shortly after the onset of light ('Mizuo phenomenon'; Fig. 1). The course of dark adaptation of rod photoreceptors is extremely retarded in Oguchi disease while that of cones appears to proceed normally. The locus for Oguchi disease was recently mapped between D2S172 and D2S345 on distal chromosome 2q by linkage analysis. Interestingly, the gene for arrestin, an intrinsic rod photoreceptor protein implicated in the recovery phase of light transduction, also maps to this region of chromosome 2q (refs 6, 7). Here we report that in five out of six unrelated Japanese patients with Oguchi disease, we have identified a homozygous deletion of nucleotide 1147 (1147delA) in codon 309 of the arrestin gene, predicting a shift in the reading frame and a premature termination of translation which may result in 'functional null alleles.'

Language regression in childhood

Language regression is observed both in autistic regression and as part of acquired epileptic aphasia (Landau-Kleffner Syndrome). We prospectively identified 177 children with language regression at four major medical centers, and their clinical characteristics were recorded. Their mean age at regression was 22.8 months. The mean time-to-specialist referral was 38 months of age. Most children (88%) met criteria for autism or manifested autistic features. Males (P = 0.02) and children less than 3 years of age who regressed (P = 0.016) had a higher probability of developing autistic behaviors. Seizures were more common in children who regressed after they reached 3 years of age (P < 0.001), and children with seizures were less likely to have associated autistic regression (P < 0.001). Electroencephalogram abnormalities were reported in 37% of patients and were more common in children with seizures (P < 0.001). At last follow-up, language function was impaired in 88% of the children, although some improvement was noted in 57%. We conclude that the loss of previously acquired language at any age, even if that language only includes a few words or communicative gestures, is often associated with a more global regression in cognition and/or behavior and has serious implications for future function. Early identification and referral of these children is necessary to allow for diagnosis and intervention.

Mitochondrial mutation associated with nonsyndromic deafness

PURPOSE

The first mutation associated with nonsyndromic deafness has recently been identified in pedigrees with susceptibility to aminoglycoside ototoxicity and in a large Arab-Israeli pedigree. The mutation is maternally transmitted, and is a nucleotide substitution in the mitochondrial 12S ribosomal RNA gene. A different sequence change, in the mitochondrial tRNA(Ser)(UCN)/COI gene, has been proposed as a candidate mutation in a Scottish nonsyndromic deafness pedigree. We have now identified a family in New Zealand with maternally inherited nonsyndromic sensorineural deafness, and the purpose of the current study is to identify the molecular basis of deafness in this family.

MATERIALS AND METHODS

A family tree was established by history and chart review, and audiological and clinical data were obtained. Blood was sampled from 10 family members, and lymphoblastoid cell lines were established for 4 of them. The DNA of these individuals was extracted, and the mitochondrial genome was analyzed by Southern blot analysis for gross rearrangements. Subsequently, the entire coding sequence of the mitochondrial genome was sequenced, compared to the normal sequence, and all sequence variations were analyzed by allele-specific oligonucleotide hybridization or restriction enzyme analysis.

RESULTS

Several candidate mutations were identified, one of them being the nucleotide 7445 A-->G mutation in the mitochondrial tRNAser(UCN)/COI gene. This mutation was heteroplasmic and identical to the one previously identified in the Scottish pedigree.

CONCLUSIONS

The finding of the same heteroplasmic mutation in two independent pedigrees with the same phenotype and transmission pattern, establishes this sequence change as the most likely determinant of the deafness phenotype in these families. This implies that nonsyndromic deafness can be caused by mutations in generalized cell processes, such as oxidative phosphorylation, rather than in hearing specific molecules.

Establishment of functional imprinting of the H19 gene in human developing placentae

We have found that the imprinted H19 gene can be expressed either biallelically or monoallelically in the developing human placentae. H19 biallelic expression is confined to the placenta until 10 weeks of gestation, after which it becomes exclusively maternal, and does not affect allele-specificity or levels of IGF2 expression. The promoter region of H19 is hypomethylated at all stages of placental development, while the 3' portion shows progressive methylation of the paternal allele with gestation. Our observations demonstrate that the establishment of functional H19 imprinting occurs during the early development of the placenta and provide an opportunity to understand the mechanism by which the H19 primary imprint is manifested in somatic cells.

Epidemiology and control of vancomycin-resistant enterococci in a regional neonatal intensive care unit

BACKGROUND

After the occurrence of two cases of bloodstream infection with vancomycin-resistant enterococci (VRE) in our regional neonatal intensive care unit, we studied the epidemiology of VRE and applied extensive infection control measures to the unit to control VRE transmission.

METHODS

Infection control measures applied to the unit included weekly surveillance for VRE colonization; education; cohorting of VRE-positive, VRE-negative and VRE-exposed babies with separate personnel and equipment for each group; use of gowns and gloves on room entry; and hand washing before and after each patient contact. Risk factors for VRE colonization were determined with a stepwise logistic regression model.

RESULTS

Thirty-three (40.2%) babies became colonized with VRE. The VRE colonization rate was reduced from 67% to 7% after implementation of infection control measures. Prolonged antimicrobial treatment and low birth weight were significantly associated with an increased risk of VRE colonization.

CONCLUSION

VRE can spread rapidly among newborns in a regional neonatal intensive care unit. Strict infection control measures can reduce the rate of VRE colonization among neonates.

Linkage of blepharophimosis syndrome in a large Indian pedigree to chromosome 7p

Blepharophimosis syndrome (BPES) is an autosomal dominant disorder involving abnormal eyelid development. Cytogenetic and linkage analyses have previously implicated the chromosome 3q23 region in multiple cases of this syndrome. However, in a few cases cytogenetic analyses have implicated other chromosomal regions in this condition. Here we report linkage of BPES in a large Indian pedigree to chromosome 7p13-p21; affected only two-point and multipoint analyses using D7S488, D7S2551 and D7S2562 both showed peak lod scores of 3.61 coincident with D7S2562. Recombinations in affected individuals placed the critical region between D7S488 and D7S629. When both affected and unaffected individuals were considered, a maximum two-point lod score of 3.38 at theta = 0.08 was obtained with D7S2551 while a peak multipoint lod score of 3.64 was obtained between D7S488 and D7S2551. Segregation analysis revealed two unaffected individuals carrying the affected haplotype accounted for the difference in peak, relative to the affected only analysis. The chromosome 7p candidate genes inhibin beta A and epidermal growth factor receptor map outside this region whereas the HOX1 gene cluster may map inside this region. Although BPES is sometimes associated with female infertility due to premature ovarian failure, in the current family affected females were fertile. The current finding together with the previous evidence implicating chromosome 3q2 provides strong evidence that BPES involves locus heterogeneity; this point should be considered when counselling affected families.

Weakness in pregnancy - expect the unexpected

Guillain-Barré syndrome (GBS) is rare in pregnancy with an incidence estimated to be between 1.2 and 1.9 cases per 100,000 people annually, and it is generally accepted that it carries a high maternal risk. Delayed diagnosis is common because the initial non-specific symptoms may mimic changes in pregnancy. GBS should be considered in any pregnant patient complaining of muscle weakness, general malaise, tingling of the fingers and respiratory discomfort. This case aims to highlight the importance of early diagnosis, allowing prompt initiation of the immunomodulatory treatments which have been shown to improve outcome alongside multidisciplinary care.

How I do it: Simple and effortless approach to identify thoracodorsal nerve on axillary clearance procedure

Breast cancer surgery frequently involves an axillary clearance procedure for nodal metastases. Injury to the thoracodorsal nerve is one of the complications related to the axillary dissection. The thoracodorsal nerve innervates the latissimus dorsi muscle which facilitates in certain movements of the arm. Moreover, it can be used as a nerve graft in long thoracic nerve injury whether in trauma or surgery. Understanding the anatomy structures and good surgical technique in the axillary clearance procedure can identify and prevent such an injury to the thoracodorsal nerve. Here, we demonstrate a simple and effortless technique for identification of the thoracodorsal nerve during axillary surgery.

Efferent limb of gastrojejunostomy obstruction by a whole okra phytobezoar: Case report and brief review

A phytobezoar is one of the intraluminal causes of gastric outlet obstruction, especially in patients with previous gastric surgery and/or gastric motility disorders. Before the proton pump inhibitor era, vagotomy, pyloroplasty, gastrectomy and gastrojejunostomy were commonly performed procedures in peptic ulcer patients. One of the sequelae of gastrojejunostomy is phytobezoar formation. However, a bezoar causing gastric outlet obstruction is rare even with giant gastric bezoars. We report a rare case of gastric outlet obstruction due to a phytobezoar obstructing the efferent limb of the gastrojejunostomy site. This phytobezoar which consisted of a whole piece of okra (lady finger vegetable) was successfully removed by endoscopic snare. To the best of our knowledge, this is the first case of okra bezoar-related gastrojejunostomy efferent limb obstruction reported in the literature.

The effect on mitochondrial function of the tRNA Ser(UCN)/COI A7445G mtDNA point mutation associated with maternally-inherited sensorineural deafness

An A to G point mutation at nucleotide position 7445 in the mitochondrial DNA genome is associated with maternally-inherited sensorineural deafness in two separate human pedigrees. To determine whether this point mutation [tRNA(SER)UCN)/COI A7445G] led to sensorineural deafness by affecting cellular energy metabolism we investigated the bioenergetic function of mitochondria in lymphoblastoid cultures established from these patients. Even though essentially all of the mitochondrial DNA in these cells contained the mutation at nucleotide position 7445, there was no effect on a number of mitochondrial bioenergetic functions (mitochondrial content, membrane potential in both intact and digitonin-permeabilised cells, cellular ATP/ADP ratios and respiratory enzyme activity) when compared with control cells. The implications of these findings for both the aetiology of the sensorineural deafness associated with the A7445G mtDNA mutation, and the role of bioenergetic defects in mitochondrial DNA diseases in general are discussed.

Atypical myocardial infarction and hypertension: an inner city experience

The clinical features of 304 patients with acute myocardial infarction with and without hypertension were studied retrospectively. This inner city population consisted of 172 (57%) males and 132 (43%) females; 155 (51%) patients were black, 88 (29%) Hispanic, and 61 (20%) white by self-identification. Hypertension (greater than or equal to 160/95 mmHg) was present on admission in 46% (139) of patients. Typical ischaemic chest pain was the most common presenting symptom and occurred with a similar frequency in patients with and without hypertension. However, the group with hypertension consisted of proportionately more females than males, more frequently had previously diagnosed hypertension and congestive heart failure, and more often presented with shortness of breath and pulmonary oedema. The racial distribution, mean ages, prevalence of angina, previous myocardial infarction, diabetes, smoking, family history of cardiovascular disease, type of myocardial infarction, peak creatinine phosphokinase, plasma cholesterol, and mortality rates were similar in both groups. Thus, female sex, history of hypertension, history of congestive heart failure, and pulmonary oedema characterised patients with compared to those without hypertension. These findings suggest that the higher mortality rate observed in hypertensives during follow-up after myocardial infarction may be due, at least in part, to more severe underlying left ventricular dysfunction.