Excess paternal age in apparently sporadic osteogenesis imperfecta.

The objective of this study was to examine whether parental age is associated with the occurrence of apparently sporadic osteogenesis imperfecta (OI). We compared parental age and the joint distribution of maternal and paternal age with expected distributions based on statutory birth records for each year and location of birth. The study included patients with OI based in the United Kingdom. The study was restricted to cases born in England, Wales, and Scotland between 1961 and 1998. Subgroup analysis was by clinical type [Sillence et al., 1979: J Med Genet 16:101-116] and apparent mode of inheritance based on pedigree analysis. Of 730 eligible cases, 357 were apparently sporadic. The mean age of fathers at birth of children with apparently sporadic OI was 0.87 years greater than expected (P = 0.010; 95% confidence interval = 0.21 to 1.54 years). The relative risk was 1.62 for fathers in the highest quintile of paternal age compared with fathers in the lowest quintile. The magnitude of the paternal age excess did not differ significantly between Sillence types (analysis of variance P = 0.534). In sporadic cases, paternal age was 0.51 years greater than expected, given maternal age, year, and location of birth (P = 0.033). In contrast, in familial cases, there was no significant paternal age excess, and paternal age was not significantly different from that expected given maternal age. Increased paternal age is a significant risk factor for sporadic OI. This effect is not accounted for by increasing maternal age. The magnitude of the paternal age excess is small in comparison with that in some other autosomal dominant disorders.

How common is hearing impairment in osteogenesis imperfecta?

Hearing impairment has long been recognized as a common feature in osteogenesis imperfecta. The figures in some publications could be taken to imply that, with increasing age, the proportion of osteogenesis imperfecta patients with hearing impairment approaches 100 per cent. The incidence of hearing loss in a large survey of 1394 patients with osteogenesis imperfecta was examined. It was found that the most common age of onset was in the second, third and fourth decades of life. At the age of 50 approximately 50 per cent of the patients had symptoms of hearing impairment; over the next 20 years there was little further increase. Differences were shown between patients with different clinical types of osteogenesis imperfecta as delineated in the Sillence classification; hearing loss was significantly less common in the type IV disease than in the type I disorder. Among the 29 families with osteogenesis imperfecta type IA there were distinct differences in the likelihood of hearing loss. These findings provide insights which will be valuable in giving patients advice on the likelihood of developing hearing loss in the future.

Causes of death in osteogenesis imperfecta.

AIMS: To determine the causes of death in patients with osteogenesis imperfecta, excluding infants with the perinatal lethal form (type II). METHODS: Seventy nine patients with known osteogenesis imperfecta were identified, 37 of whom had been seen clinically in life. Causes of death were identified from death certificates, postmortem reports, medical records, hospital consultants, relatives, and the Brittle Bone Society's records. RESULTS: Patients with the milder types of osteogenesis imperfecta, I and IV, often had a normal lifespan and died of unrelated illnesses such as myocardial infarction and malignancy. In some of these patients and in many patients with the more severe type III disease, it was clear that osteogenesis imperfecta contributed significantly to death, almost certainly to many of the respiratory deaths and to deaths from cardiac failure due to kyphoscoliosis. Osteogenesis imperfecta also caused six deaths, directly or indirectly, due to basilar invagination of the skull. Osteogenesis imperfecta may have contributed to deaths from intracranial bleeding. Apparently minor traumatic incidents may have disastrous consequences in patients with this disorder. CONCLUSIONS: Prompt care for respiratory infections and prevention of trauma in patients with osteogenesis imperfecta is essential.

Osteogenesis imperfecta: the distinction from child abuse and the recognition of a variant form.

Unexplained fractures are characteristic of both osteogenesis imperfecta (OI) and non-accidental injury (NAI) but in most cases the diagnosis is straightforward. However, in a few OI patients an initial diagnosis of NAI is made. Factors contributing to such difficulties include failure to recognise that OI can occur without a family history, without blue sclerae, without osteopenia, without an excess of Wormian bones, or with metaphyseal fractures. In addition we report on 39 patients with an unusual history in that fractures only occurred in the first year of life. Rib fractures, metaphyseal abnormalities and periosteal reactions were common. The initial diagnosis was usually OI if the fractures occurred in hospital, but NAI if they appeared to have been sustained at home. Additional findings such as anaemia, vomiting, hepatomegaly, and apnoeic attacks were often found in these patients. The disorder has some similarities to the syndrome of infantile copper deficiency. Like the latter it is particularly common in preterm infants and in twins. Therefore, we are attempting to examine the incidence of significant hypocupraemia in unselected preterm infants. We suggest that the likely cause of this "temporary brittle bone disease" is a temporary deficiency of an enzyme, perhaps a metalloenzyme, involved in the post-translational processing of collagen.

Psychiatric morbidity in primary hyperparathyroidism.

Psychiatric symptoms are well recognized as a feature of patients with primary hyperparathyroidism. We have applied a standardized psychiatric interview to 15 patients before and after surgery. Thirteen had a lower 'psychiatric score' (less psychiatric morbidity) after surgery and improvements were particularly seen in symptoms of fatigue, depression, irritability, sleep disturbance and lack of concentration. The levels of intellectual impairment and of anxiety were unchanged after surgery. The 'psychiatric scores' in an additional group of 21 hyperparathyroid patients, in whom a decision to treat conservatively had been made independently, were similar to those in the surgically treated patients after surgery. Among all the untreated patients no relationship was found between overall 'psychiatric score' and serum levels of calcium or parathyrin.

Clinical and radiological features of osteogenesis imperfecta type IVA.

This paper reports a survey of 78 patients with osteogenesis imperfecta (OI) type IVA, the variant that causes the greatest difficulties in differential diagnosis. A subgroup of children aged between five and eleven were compared with a control group from local schools. Among the OI children there were, apart from the high number of fractures, also significantly increased incidences of bruising, nosebleeds, excessive sweating and hypermobility of joints. Although none of the children with OI type IV had the dark blue or grey sclerae of the type I disease, an appreciable number had pale blue sclerae in early childhood. Radiologically normal bone texture was seen at the time of the first fracture in 10 out of 17 patients. Hypertrophic callus was seen in five patients and metaphyseal fractures in four. We hope that the information on this large group of patients will assist in the prevention of diagnostic difficulties.

Risk of dominant mutation in older fathers: evidence from osteogenesis imperfecta.

The mean paternal age at birth of 80 presumed mutant cases of dominant osteogenesis imperfecta (OI) was significantly higher than that of population controls and remained so after adjusting for maternal age. There was also an increase in mean maternal age (not significant) which disappeared after adjusting for paternal age. No significant increase in maternal or paternal age was found in cases having OI either of a dominant type with an affected parent or of a type (Sillence type III) usually regarded as recessive. We conclude that, as in certain other dominant conditions, the risk of mutant OI increases with paternal age. However, the rate of increase of risk with paternal age appears to be considerably lower than, for example, in achondroplasia. The overall risk of fresh dominant mutation in older fathers may therefore be lower than has previously been suggested.

Osteogenesis imperfecta after the menopause.

We studied the fracture rate as a function of age in 45 women and 20 men with osteogenesis imperfecta. In each variant of the disorder, the fracture rate in women peaked in childhood, declined in adolescence, and rose again after the menopause. In contrast, the fracture rate in men remained low after adolescence. After the menopause women were vulnerable to crush fractures of the spine as well as fractures of the long bones. We conclude that the increased fracture rate after the menopause in women with osteogenesis imperfecta reflects the superimposition of the effects of age-related bone loss on those of the defective collagen structure of osteogenesis imperfecta, and that hormone-replacement therapy may be specifically indicated in this group of patients from the time of the menopause. We also suggest that osteogenesis imperfecta should be included in the differential diagnosis of women presenting with crush fractures of the spine.

Heterogeneity of osteogenesis imperfecta type I.

We have studied 166 patients from 71 families with Sillence type I osteogenesis imperfecta (dominant inheritance and blue sclerae). We confirm earlier findings that there are two subgroups, those with and those without dentinogenesis imperfecta; each family can be allocated to one or other group. Our confidence that the two groups represent distinct disorders is increased by finding that the patients with dentinogenesis imperfecta differ not only in their dental characteristics but also in other clinical features. They have a more severe disease with a greater fracture rate and a greater likelihood of growth impairment.

Osteogenesis imperfecta with dominant inheritance and normal sclerae.

Most patients with dominantly inherited osteogenesis imperfecta have blue sclerae and relatively mild symptoms. However, in a small group of families the patients have normal sclerae and this disorder has been classified as Type 4 osteogenesis imperfecta. This paper reports the clinical and radiographical features of 48 patients from 16 families with Type 4 osteogenesis imperfecta and compares the findings with those of the classical disorder with blue sclerae (Type 1 osteogenesis imperfecta). The two types are similar in usually causing a mild disease but with a wide range of severity, and in both types the rate of fracture declines in adolescence. There are, however, some significant differences apart from the colour of the sclerae. In Type 4 the first fracture more commonly occurs at birth, dentinogenesis imperfecta is more frequent than in Type 1 and bruising and nose-bleeds are less common. As in Type 1, the radiographic appearances of the bones may be normal. It is important that Type 4 osteogenesis imperfecta should be recognised because of the need for competent genetic counselling, because the management may be different from that appropriate for Type 1 and because it may be mistaken for idiopathic juvenile osteoporosis or child abuse.

Medicines evaluation and monitoring group: central nervous system effects of pentazocine.

Hospital-based drug monitoring facilities have been used to investigate the frequency of perceptual disturbances in inpatients receiving pentazocine and the occurrence of dependence upon this drug after discharge from hospital. A pilot study was carried out in which seven out of 70 hospital inpatients receiving pentazocine reported such episodes, while in a prospective study, 9 out of 132 patients receiving pentazocine and 1 out of 112 receiving cyclimorph, dihydrocodeine, or pethidine reported their occurrence. A total of 135 patients who received pentazocine for disorders likely to require longterm analgesia were followed up for six months after their discharge from hospital. 24 had received pentazocine after discharge; two required an increase in dosage and four expressed a preference for pentazocine.