Differences in carrier frequency between mothers of Duchenne and Becker muscular dystrophy patients.

Duchenne and Becker muscular dystrophies (DMD/BMD) are X-linked inherited muscular disorders caused by mutations in the dystrophin gene. Two-thirds of DMD cases are thought to be caused by inheritance from carrier mothers and this study aimed to clarify and compare the carrier frequency of mothers of DMD and BMD patients according to the mutation type. We included 139 DMD and 19 BMD mothers. Of these, 113 patients (99 DMD and 14 BMD) and 13 patients (12 DMD and 1 BMD) had deletions and duplications of one or more exons, respectively. Small mutations, including nonsense mutations, small deletions/insertions and splice site mutations, were identified in 32 patients (28 DMD and four BMD). The overall carrier frequency for BMD mothers was significantly higher than for DMD (89.5% vs 57.6%, P<0.05), probably as BMD patients can leave descendants. The carrier frequency tended to be lower in mothers of DMD patients with deletion mutations than with duplications and small mutations (53.5%, 66.7% and 67.9%, respectively). It was suggested that de novo mutations are more prevalent for deletions than other mutations. This is the first report to analyze the carrier frequency according to mutation type.

[Clinical manifestations of three neonates with family histories of Menkes disease].

OBJECTIVE: To examine indications for the early diagnosis of Menkes disease (MD). METHODS: We compared clinical examination results of 3 neonate males with family histories of MD who were at risk of being affected (1 infant was affected and 2 were unaffected). RESULTS: Kinky hair, a characteristic shown by MD patients, was observed just after birth in the affected infant; however, this characteristic was extremely mild and easy to miss. In the first month after birth, serum copper level declined over time in the affected infant,while it increased in the unaffected infants. Urine homovanillic acid/vanillylmandelic acid (HVA/VMA) ratio, which is typically high in MD patients, was observed to be 4.9-8.0 (cut-off, 4.0) in the affected infant. In the unaffected infants, the urine HVA/MVA ratio showed a high value of 11.0 during catecholamine administration, but this decreased to below the cut-off value when catecholamine was not administered. CONCLUSIONS: Variations in the serum copper level and urine HVA/VMA ratio over time were considered as useful indicators for the early diagnosis of MD.

Standard values for the urine HVA/VMA ratio in neonates as a screen for Menkes disease.

BACKGROUND: Menkes disease is a lethal disorder associated with copper metabolism. Although early treatment with copper-histidine injections can improve outcomes, early diagnosis is difficult because the clinical features of Menkes disease are subtle or do not manifest in affected neonates. Previous report stated that the low activity of dopamine ß-hydroxylase, a copper-dependent enzyme, leads to increases in the urine homovanillic acid/vanillylmandelic acid (HVA/VMA) ratios in patients with Menkes disease, and indicated that a urine HVA/VMA ratio cut-off value of >4 is useful in screening for Menkes disease. METHODS: We examined the standard values of the urine HVA/VMA ratio in unaffected neonates and assessed its use as a screening parameter for Menkes disease among neonates. In total, 112 neonates, aged between 1 and 6 days, were enrolled in the study and were classified into 2 groups based on their urine HVA/VMA ratios: high (>4) and low (⩽ 4). RESULTS: Multivariate logistic analysis revealed that mechanical ventilation was an independent risk factor for a high urine HVA/VMA ratio (odds ratio: 21.94; 95% confidence interval: 2.82-247.03; p=0.004). The mean urine HVA/VMA ratio was 2.47 ± 0.67 among 92 neonates who did not receive mechanical ventilation. CONCLUSION: This study established standard values for the urine HVA/VMA ratio in newborn babies that could be useful in screening for Menkes disease among neonates.

A Japanese child with geleophysic dysplasia caused by a novel mutation of FBN1.

Geleophysic dysplasia (GD) is a rare disorder characterized by severe short stature, short hands and feet, limited joint mobility, skin thickening, characteristic facial features (e.g., a "happy" face), and cardiac valvular disorders that often result in an early death. The genes ADAMTSL2 (a disintegrin-like and metalloprotease with thrombospondin type 1 motif-like 2) and FBN1 (fibrillin 1) were recently identified as causative genes for GD. Here, we describe a 10-year-old Japanese female with GD who was born to non-consanguineous parents. At the age of 11 months, she was referred to our hospital because of very short stature for her age (-4.4 standard deviations of the age-matched value) and a "happy" face with full cheeks, a shortened nose, hypertelorism, and a long and flat philtrum, characteristic of GD. Her hands and feet were small, her skin was thickened, and her joint mobility was generally limited. She had cardiac valvular disorders and history of recurrent respiratory failure. Mutation analysis revealed no abnormalities in ADAMTSL2. However, analysis of FBN1 revealed a novel heterozygous mutation (c.5161T>T/G) in exon 41, which encodes transforming growth factor-ß-binding protein-like domain 5 (TB5). GD is an extremely rare disorder and, to our knowledge, only one case of GD with an FBN1 mutation has been reported in Japan. Similar to the previously reported cases of GD, the mutation in the current patient was located in the TB5 domain, which suggests that abnormalities in this domain of FBN1 are responsible for GD.