Molecular basis of von Hippel-Lindau syndrome in Chinese patients

Background  Von Hippel-Lindau (VHL) syndrome is an autosomal dominant familial cancer syndrome predisposing the affected individuals to multiple tumours in various organs. The genetic basis of VHL in Southern Chinese is largely unknown. In this study, we characterized the mutation spectrum of VHL in nine unrelated Southern Chinese families.

Methods  Nine probands with clinical features of VHL, two symptomatic and eight asymptomatic family members were included in this study. Prenatal diagnosis was performed twice for one proband. Two probands had only isolated bilateral phaeochromocytoma. The VHL gene was screened for mutations by polymerase chain reaction, direct sequencing and multiplex ligation-dependent probe amplification (MLPA).

Results  The nine probands and the two symptomatic family members carried heterozygous germline mutations. Eight different VHL mutations were identified in the nine probands. One splicing mutation, NM_000551.2: c.463+1G>T, was novel. The other seven VHL mutations, c.233A>G [p.Asn78Ser], c.239G>T [p.Ser80Ile], c.319C>G [p.Arg107Gly], c.481C>T [p.Arg161X], c.482G>A [p.Arg161Gln], c.499C>T [p.Arg167Trp] and an exon 2 deletion, had been previously reported. Three asymptomatic family members were positive for the mutation and the other five tested negative. In prenatal diagnosis, the fetuses were positive for the mutation.

Conclusions  Genetic analysis could accurately confirm VHL syndrome in patients with isolated tumours such as sporadic phaeochromocytoma or epididymal papillary cystadenoma. Mutation detection in asymptomatic family members allows regular tumour surveillance and early intervention to improve their prognosis. DNA-based diagnosis can have an important impact on clinical management for VHL families. 

     

Enzyme replacement therapy for mucopolysaccharidosis VI (Maroteaux-Lamy syndrome): experience in Hong Kong

Mucopolysaccharidosis VI (Maroteaux-Lamy syndrome) is a very rare inherited lysosomal storage disease. We evaluated the efficacy and safety of weekly infusions of recombinant human arylsulfatase B as enzyme replacement therapy for two patients in whom this condition was advanced. The primary outcome variables were the distance walked in a 6-minute walk test, forced vital capacity, and ejection fraction. The secondary outcome variables were the number of stairs climbed in a 3-minute stair climbing test, joint mobility, urinary glycosaminoglycan excretion, auto-continuous positive airway pressure study and liver size. After 24 weeks of treatment, patient A walked 40 m (36%) and patient B walked 66 m (58%) more in the walk test than at baseline. After 48 weeks, in patient A the corresponding improvements were 142 m (129%) in the walk test and 33 stairs (60%) in the 3-minute stair climbing test, and in patient B the respective improvements were 198 m (174%) and 77 stairs (140%). There was a significant decline in urinary glycosaminoglycan excretion and improvement in range of motion of joints in both patients. The auto-continuous positive airway pressure study revealed improvements in patient A, while other efficacy variables remained static. There were no drug-related adverse events or allergic reactions reported during and after the infusions of recombinant human arylsulfatase B. Recombinant human arylsulfatase B significantly improves endurance and reduces urinary glycosaminoglycan excretion. The drug is generally safe and well tolerated.     

Etiology and predictors of urinary incontinence and its effect on quality of life

Aim: Urinary incontinence associated with dementia can result in medical comorbidities. We aimed to determine the prevalence of urinary incontinence and to identify the etiology and factors associated with urinary incontinence in dementia patients. Methods: Patients with an Mini‐Mental State Examination (MMSE) score of more than 10, attending the memory clinic were recruited. Basic demographic data, types and duration of dementia, use of cholinesterase inhibitor and other drugs with anticholinergic effects, carer stress and presence of urinary incontinence in the previous 6 months were recorded. Urodynamic studies were carried out in those patients with urinary incontinence. Results: One hundred and forty‐four subjects with a mean age of 78 years (standard deviation 6.8) were included. Forty‐eight (33.3%) had urinary incontinence. There was no statistically significant difference between continent and incontinent groups regarding age, MMSE, duration of dementia, use of cholinesterase inhibitor and of drugs with anticholinergic effects. Presence of nocturia of more than twice per night (odds ratio [OR] 4, 95% confidence interval [CI] 1.7, 9.2), use of walking aids (OR 2.6, 95% CI 1.1, 5.9) and male sex (OR 1.36, 95% CI 1.1, 5.2) were independent predictors of urinary incontinence. Urodynamic studies showed that 21 subjects had detrusor overactivity, 13 had bladder outlet obstruction, two with low compliance bladder, two with small bladder capacity, four with detrusor hyperactivity and impaired contractility. Conclusion: Urinary incontinence commonly occurs in dementia subjects. Poor mobility and presence of nocturia increase the risk of urinary incontinence. Correction of the possible reversible factors may help to reduce the prevalence of urinary incontinence in patients with dementia and reduce carer stress.     

Quality of life measurement in vitiligo. Position statement of the European Academy of Dermatology and Venereology Task Force on Quality of Life and Patient Oriented Outcomes with external experts

Members of the European Academy of Dermatology and Venereology (EADV) Task Force on Quality of Life (QoL) and Patient Oriented Outcomes reviewed the instruments available for health-related (HR) QoL assessment in vitiligo and together with external vitiligo experts (including representatives of the EADV Vitiligo Task Force) have made practical recommendations concerning the assessment of QoL in vitiligo patients. The Dermatology Life Quality Index (DLQI) was the most frequently used HRQoL instrument, making comparison of results between different countries possible. Several vitiligo-specific instruments were identified. The vitiligo Impact Scale (VIS) is an extensively validated vitiligo-specific HRQoL instrument with proposed minimal important change and clinical interpretation for VIS-22 scores. VIS-22 was developed for use in India, where there are some specific cultural beliefs concerning vitiligo. The EADV Task Force on QoL and Patient Oriented Outcomes recommends use of the DLQI and the Children's Dermatology Life Quality Index (CDLQI) as dermatology-specific instruments in vitiligo. There is a strong need for a valid (including cross-cultural validation) vitiligo-specific instrument that can be either a new instrument or the improvement of existing instruments. This validation must include the proof of responsiveness.