Differentiation of child abuse from osteogenesis imperfecta

Standardizing genetic and metabolic consults for non-accidental trauma at a large pediatric academic center

BACKGROUND

Evaluations of suspected non-accidental trauma (NAT) often include consultation with genetic and metabolic teams to assess patients for rare genetic conditions that can mimic or exacerbate child abuse. Diagnoses that may be questioned during court proceedings include osteogenesis imperfecta (OI) and glutaric aciduria type 1 (GA1). Currently there are no official society guidelines for the genetic or metabolic workup of suspected NAT.

OBJECTIVE

To standardize consult recommendations for suspected NAT through collaboration between the Genetics and Genomics Division and the Child Protection Team (CPT).

PARTICIPANTS AND SETTINGS

Children evaluated for suspected NAT at a single pediatric referral center.

METHODS

A year of inpatient consult requests for suspected NAT to the genetics division were reviewed. The most common indications for consult were fractures and subdural hematoma. Consult recommendations for similar indications varied between providers. A standard operating procedure (SOP) with specific recommendations for suspected NAT consults for fractures, intracranial hemorrhage, and other indications was created based on expert reviews and other relevant literature. A questionnaire assessing division practice patterns for these consults was distributed both pre (n = 17) and post-introduction of the SOP (n = 11).

RESULTS

Adherence to the SOP and impact on suspected NAT consult recommendations were assessed at 18 months after SOP introduction. Consult recommendations were in line with the SOP for 7/11 consults pre-intervention and 6/7 consults post-intervention. Providers were more likely to report feeling extremely or very confident they were using evidence-based medicine for NAT consults post-intervention.

Debunking Fringe Beliefs in Child Abuse Imaging: AJR Expert Panel Narrative Review

Child abuse is a global public health concern. Injuries from physical abuse may be clinically occult and not appreciable on physical examination. Imaging is therefore critical in identifying and documenting such injuries. The radiologic approach for a child who has potentially been abused has received considerable attention and recommendations according to decades of experience and rigorous scientific study. Nonetheless, fringe beliefs describing alternative explanations for child abuse-related injuries have emerged and received mainstream attention. Subsequently, imaging findings identified in abused children have been attributed to poorly supported underlying medical conditions, clouding the evidence basis for radiologic findings indicative of nonaccidental trauma. Fringe beliefs that attribute findings seen in child abuse to alternate pathologies such as genetic disorders, birth trauma, metabolic imbalances, vitamin D deficiency, and short-distance falls typically have limited evidence basis and lack professional society support. Careful review of the scientific evidence and professional society consensus statements is important in differentiating findings attributable to child abuse from fringe beliefs used to discount the possibility that a child's constellation of injuries is consistent with abuse. This review refutes fringe beliefs used to provide alternative explanations in cases of suspected child abuse and reinforces the key literature and scientific consensus regarding child abuse imaging.

Osteogenesis imperfecta misdiagnosed as child abuse

The differential diagnosis of child abuse includes osteogenesis imperfecta (OI). Mild phenotypes of OI may be misdiagnosed as child abuse. The purpose of this study was to review the experience of families in which OI was misdiagnosed as child abuse. Sixty-one potential cases of misdiagnosis were identified from a lay support organization. Upon review of the medical records, 33 cases were identified with a confirmed diagnosis of OI (skin biopsy or DNA blood test). Questionnaires were given to families to describe their condition and experiences. There were 19 male and 14 female children. Mean age at presentation was 7.1 months (range: 1-23 months). All patients had fractures and the presenting symptoms included pain (n=14), swelling (n=7), decreased limb movement (n=5), or unusual limb position (n=2). Abnormal radiograph findings consistent with OI were found in 19 of 33 patients (58%), clinical findings of OI were present in 23 of 33 patients (70%), and a family history that could be supportive of OI was present in 18 of 33 families (55%). Children were removed from the family in 70% of cases and older siblings were removed from the family in 62% of cases. The mean age at the time of diagnosis of OI was 10.5 months (range: 3-35 months). The consequences of misdiagnosis of OI as child abuse are devastating to the family. OI should be considered in all cases of suspected child abuse. In children with any clinical, radiographic, or family history features of OI, early involvement of a bone specialist and performance of laboratory testing should be considered to establish a timely and accurate diagnosis.

Osteogenesis Imperfecta: A Review with Clinical Examples

Osteogenesis imperfecta (OI) is characterized by susceptibility to bone fractures, with a severity ranging from subtle increase in fracture frequency to prenatal fractures. The first scientific description of OI dates from 1788. Since then, important milestones in OI research and treatment have, among others, been the classification of OI into 4 types (the 'Sillence classification'), the discovery of defects in collagen type I biosynthesis as a cause of most cases of OI and the use of bisphosphonate therapy. Furthermore, in the past 5 years, it has become clear that OI comprises a group of heterogeneous disorders, with an estimated 90% of cases due to a causative variant in the COL1A1 or COL1A2 genes and with the remaining 10% due to causative recessive variants in the 8 genes known so far, or in other currently unknown genes. This review aims to highlight the current knowledge around the history, epidemiology, pathogenesis, clinical/radiological features, management, and future prospects of OI. The text will be illustrated with clinical descriptions, including radiographs and, where possible, photographs of patients with OI.

EMQN best practice guidelines for the laboratory diagnosis of osteogenesis imperfecta

Osteogenesis imperfecta (OI) comprises a group of inherited disorders characterized by bone fragility and increased susceptibility to fractures. Historically, the laboratory confirmation of the diagnosis OI rested on cultured dermal fibroblasts to identify decreased or abnormal production of abnormal type I (pro)collagen molecules, measured by gel electrophoresis. With the discovery of COL1A1 and COL1A2 gene variants as a cause of OI, sequence analysis of these genes was added to the diagnostic process. Nowadays, OI is known to be genetically heterogeneous. About 90% of individuals with OI are heterozygous for causative variants in the COL1A1 and COL1A2 genes. The majority of remaining affected individuals have recessively inherited forms of OI with the causative variants in the more recently discovered genes CRTAP, FKBP10, LEPRE1,PLOD2, PPIB, SERPINF1, SERPINH1 and SP7, or in other yet undiscovered genes. These advances in the molecular genetic diagnosis of OI prompted us to develop new guidelines for molecular testing and reporting of results in which we take into account that testing is also used to ‘exclude' OI when there is suspicion of non-accidental injury. Diagnostic flow, methods and reporting scenarios were discussed during an international workshop with 17 clinicians and scientists from 11 countries and converged in these best practice guidelines for the laboratory diagnosis of OI.

Temporary brittle bone disease: relationship between clinical findings and judicial outcome

There is a wide differential diagnosis for the child with unexplained fractures including non-accidental injury, osteogenesis imperfecta and vitamin D deficiency rickets. Over the last 20 years we and others have described a self-limiting syndrome characterised by fractures in the first year of life. This has been given the provisional name temporary brittle bone disease. This work had proved controversial mostly because the fractures, including rib fractures and metaphyseal fractures, were those previously regarded as typical or even diagnostic of non-accidental injury. Some have asserted that the condition does not exist. Over the years 1985 to 2000 we investigated 87 such cases with fractures with a view to determining the future care of the children. In 85 of these the judiciary was involved. We examined the clinical and radiological findings in the 33 cases in which there was a judicial finding of abuse, the 24 cases in which the parents were exonerated and the 28 cases in which no formal judicial finding was made. The three groups of patients were similar in terms of demographics, age at fracturing and details of the fractures. The clinical similarities between the three groups of patients contrast with the very different results of the judicial process.

Complete COL1A1 allele deletions in osteogenesis imperfecta

PURPOSE

To identify a molecular genetic cause in patients with a clinical diagnosis of osteogenesis imperfecta (OI) type I/IV.

METHODS

The authors performed multiplex ligation-dependent probe amplification analysis of the COL1A1 gene in a group of 106 index patients.

RESULTS

In four families with mild osteogenesis imperfecta and no other phenotypic abnormalities, a deletion of the complete COL1A1 gene on one allele was detected, a molecular finding that to our knowledge has not been described before, apart from a larger chromosomal deletion detected by fluorescent in situ hybridization encompassing the COL1A1 gene in a patient with mild osteogenesis imperfecta and other phenotypic abnormalities. Microarray analysis in three of the four families showed that it did not concern a founder mutation.

CONCLUSION

The clinical picture of complete COL1A1 allele deletions is a comparatively mild type of osteogenesis imperfecta. As such, multiplex ligation-dependent probe amplification analysis of the COL1A1 gene is a useful additional approach to defining the mutation in cases of suspected osteogenesis imperfecta type I with no detectable mutation.

Do resuscitation-related injuries kill infants and children?

Occasionally, individuals accused of inflicting fatal injuries on infants and young children will claim some variant of the "CPR defense," that is, they attribute the cause of injuries found at autopsy to their "untrained" resuscitative efforts. A 10-year (1994-2003) historical fixed cohort study of all pediatric forensic autopsies at the Miami-Dade County Medical Examiner Department was undertaken. To be eligible for inclusion in the study, children had to have died of atraumatic causes, with or without resuscitative efforts (N(atraumatic) = 546). Of these, 382 had a history of cardiopulmonary resuscitation (CPR; average age of 4.17 years); 248 had CPR provided by trained individuals only; 133 had CPR provided by both trained and untrained individuals; 1 had CPR provided by untrained individuals only. There was no overlap between these 3 distinct groups. Twenty-two findings potentially attributable to CPR were identified in 19:15 cases of orofacial injuries compatible with attempted endotracheal intubation; 4 cases with focal pulmonary parenchymal hemorrhage; 1 case with prominent anterior mediastinal emphysema; and 2 cases with anterior chest abrasions. There were no significant hollow or solid thoracoabdominal organ injuries. There were no rib fractures. The estimated relative risk of injury subsequent to resuscitation was not statistically different between the subset of decedents whose resuscitative attempts were made by trained individuals only, and the subset who received CPR from both trained and untrained individuals. In the single case of CPR application by an untrained individual only, no injuries resulted. The remaining 164 children dying from nontraumatic causes and who did not undergo resuscitative efforts served as a control group; no injuries were identified. This study indicates that in the pediatric population, injuries secondary to resuscitative efforts are infrequent or rare, pathophysiologically inconsequential, and predominantly orofacial in location. In our population, CPR did not result in any rib fractures or significant visceral injuries. Participation of nonmedical or untrained individuals in resuscitation did not increase the likelihood of injury.

Imaging of the calvarium

The skull vault consists of a multitude of flat bones held together by the cranial sutures. Radiologists encounter a vast array of calvarial pathologies that tend to cause abnormalities in thickness, abnormalities in density, focal defects, or an excess of soft tissue or bone tissue. Further anomalies related to the cranial sutures and fontanelles occur in the dynamic pediatric skull. The imaging features of the host of conditions resulting in these commonly detected calvarial abnormalities are reviewed and illustrated.

Classical osteogenesis imperfecta and allegations of nonaccidental injury

We report 12 patients with osteogenesis imperfecta initially diagnosed with nonaccidental injuries. As a result, formal hearings, care proceedings, and criminal proceedings ensued and seven of the children were removed from their parents. The features suggestive of osteogenesis imperfecta at the time of the initial investigation included a positive family history in six patients, scleral discoloration in nine, abnormally large anterior fontanels in four, excessive numbers of wormian bones in four, abnormal bone texture in two, and abnormal biochemical findings in three. There were discrepancies between the fractures and other clinical evidence of inflicted trauma. The seven patients removed from their homes eventually were returned. Five patients remained at home. Information was available on the subsequent history of the patients for an average of 4.8 years. Although seven patients have had additional fractures, there have been no additional allegations of nonaccidental injury. When investigating children with unexplained fractures, it is important to review carefully their clinical history, family history, physical examination findings, and radiographic findings. Misdiagnosing patients with nonaccidental injuries causes substantial harm to the family and particularly to the child.

The infant skull: a vault of information

The art of interpreting skull radiographs is slowly being lost as trainees in radiology see fewer plain radiographs and depend more heavily on computed tomography and magnetic resonance imaging. Nevertheless, skull radiographs still provide significant information that is helpful in finding pathologic conditions and appreciating their extents. Abnormalities in the skull may be reflected as variations in the density, size, and shape of the skull, as well as skull defects. Skeletal dysplasias may manifest as a generalized decrease in calvarial density (hypophosphatasia, osteogenesis imperfecta), a generalized increase in calvarial density (osteopetrosis), or a focal increase in density (frontometaphyseal dysplasia). Diffusely decreased or increased calvarial density is usually associated with a process that affects the entire skeleton. Therefore, correct differentiation among these dysplasias depends on other concurrent features. Decreased size of the cranial vault at birth generally implies an underlying insult to the brain, including fetal alcohol syndrome and the so-called TORCH infections (toxoplasmosis, rubella, cytomegalovirus infection, herpes simplex). Macrocephaly may result from skeletal dysplasia or an increase in the intracranial volume (eg, due to underlying anomalies of the brain such as hydrocephalus).

The lesson of temporary brittle bone disease: all bones are not created equal

Temporary brittle bone disease (TBBD) is a recently described phenotype of multiple, unexplained fractures in the first year of life and predominantly in the first 6 months of life. There is usually no other injury such as bruising, subdural hematomas, retinal hemorrhages, or other internal organ injury. The susceptibility to fracture is transient, and there are no other radiographic or biochemical abnormalities noted in the standard evaluation that might suggest an underlying cause. The child abuse and pediatric radiology communities have, for the most part, been unwilling to accept this as a real condition, for they believe it is a ruse for child abuse. This review describes the experience of the author in evaluating infants with multiple unexplained fractures and the hypothesis that has emerged for explaining TBBD. The hypothesis is a prenatal application of the mechanostat/bone loading theory of bone formation and states that TBBD is caused by fetal immobilization which leads to fetal bone unloading and transient, relative osteopenia. Such susceptible infants can fracture with routine handling and present with a pattern of fractures that is similar to that which has been thought to be highly specific for child abuse. The review presents: (a) the evidence that indicates that normal fetal movement is important for normal fetal bone strength, (b) a critique of the radiologic approach in the diagnosis of child abuse in infants with multiple unexplained fractures, (c) observations that would indicate that child abuse is unlikely in infants with TBBD, and (d) new approaches to the infant with multiple unexplained fractures that would assist in accurate diagnosis.

[Bone mineral density in children with osteogenesis imperfecta]

OBJECT

Osteogenesis imperfecta is the term used for a group of disorders of collagen synthesis which cause increased bone fragility. The aim of our study was to evaluate the BMD in patients with OI.

MATERIAL AND METHODS

We used dual-energy x ray absorptiometry, Hologic QDR 4500W (DEXA), to compare the bone mineral density (BMD) of 8 patients aged from 3 years to 20 years who had osteogenesis imperfecta with an age and sex matched control group.

RESULTS

DEXA detected highly significant differences in BMD respecting control group. The mean BMD in the patients with osteogenesis imperfecta was 62.6 % of normal in lumbar spine (p < 0.01) and 63.01 % of normal in the femoral neck (p < 0.01) using Wilcoxon test.

CONCLUSION

DEXA is an objective, reproductible and sensitive method of measurement of BMD in children. It may help to stablish the diagnosis, to asses prognosis and possibly to monitor the response to different types of treatment.

Testing for osteogenesis imperfecta in cases of suspected non-accidental injury

To evaluate if laboratory testing for osteogenesis imperfecta (OI) identifies children unrecognised by clinical examination in instances where non-accidental injury (NAI) is suspected as the likely cause of fracture, we carried out a retrospective review of available medical records and biochemical test results from 262 patients. Cultured fibroblasts were received for biochemical testing for OI from children in whom the diagnosis of NAI was suspected. Eleven of the samples had alterations in the amount or structure of type I collagen synthesised, consistent with the diagnosis of OI, and in 11 others we could not exclude OI. Referring physicians correctly identified children with OI in six of the 11 instances established by biochemical studies, did not identify OI by clinical examination in three, and there was inadequate clinical information to know in two others. Biochemical testing was inconclusive in 11 infants in whom the diagnosis of OI could not be excluded, none of whom were thought to be affected by the referring clinicians. Four children believed to have OI by clinical examination had normal biochemical studies, a false positive clinical diagnosis attributed, in large part, to the use of scleral hue (a feature that is age dependent) as a major diagnostic criterion. Given the inability to identify all children with OI by clinical examination in situations of suspected NAI, laboratory testing for OI (and other genetic predispositions for fractures) is a valuable adjunct in discerning the basis for fractures and may identify a small group of children with previously undiagnosed OI.

Imaging of child abuse

Skeletal imaging plays a critical role in the diagnosis of abuse. High-detail radiographs of the entire skeleton, at times supplemented with nuclear imaging, CT, US, and MR imaging, elucidate the variety of findings with this entity. The radiologist's role includes careful analysis of clinical history, familiarity with typical osseous findings in abuse, and awareness of potential normal variants and pitfalls. An accurate diagnosis of abuse can then lead to appropriate measures to protect all family members at risk of serious injury.

Changes in clinical practice with the unravelling of diseases: connective-tissue disorders

Unravelling of diseases is achieved in steps by sequentially describing their phenotype, natural course, aetiology and pathogenesis. Through succinct clinical observation, conglomerates of heterogeneous connective-tissue disorders, such as various forms of disproportionate dwarfism, have been split into well-defined entities. They have often been confirmed by biochemical and molecular analysis. On the other hand, seemingly disparate disorders have been shown to be pathogenetically related and to be variable expressions of common defects. Examples are the mucopolysaccharidoses and type II collagenopathies. Disease recognition through splitting and lumping has improved prevention and prognostication. It is the basic requirement for future therapeutic attempts on a pathogenetic or molecular level.

Cause and clinical characteristics of rib fractures in infants

OBJECTIVE

Rib fractures are uncommon in infancy and, when diagnosed, often raise the suspicion of child abuse. However, the prevalence of other causes of rib fractures has not been well defined. The purpose of this study was to determine the causes and clinical presentations of rib fractures in infants <12 months old.

METHODS

Retrospectively, we identified all infants with rib fractures under 12 months old over a 3-year period using computerized databases at the Children's Hospital Medical Center in Cincinnati, Ohio and at the Children's Hospital, Winnipeg, Manitoba, Canada. Data extracted from the individual patient charts included: age, sex, chief complaint, number and location of rib fractures, associated injuries, birth history, history of cardiopulmonary resuscitation, and any evidence of bone dysplasia. After the chart review and a review of the radiographs by a pediatric radiologist, all fractures were determined to be attributable to one of the following causes: child abuse, birth injury, bone fragility, or accidental trauma. A determination of abuse was made when there were other injuries indicative of abuse, there was no clinical or radiographic evidence of bone fragility, there was a confession of abuse, when no reasonable history of trauma was provided, or when the history was not plausible to explain the rib fractures. Standard practice at these hospitals involves obtaining skeletal surveys on all children <2 years old when abuse is suspected. The child abuse team, which consists of physicians, nurses, and social workers, conducts these investigations and works closely with police in evaluating these children.

RESULTS

Thirty-nine infants with rib fractures were identified. Thirty-two (82%) were caused by child abuse. Three (7. 7%) were attributable to accidental injuries, 1 (2.6%) was secondary to birth trauma, and 3 (7.7%) were attributable to bone fragility. All 3 infants with fractures from accidental injury had sustained notable trauma (a motor vehicle collision, a forceful direct blow, and a fall from a height). Of the 3 infants with fractures secondary to bone fragility, 1 infant had osteogenesis imperfecta, 1 infant had rickets, and 1 infant, who was born at 23 weeks' gestation, had fragile bones attributable to prematurity.

CONCLUSIONS

Most rib fractures in infants are caused by child abuse. Although much less common, rib fractures can also occur after serious accidental injuries, birth trauma, or secondary to bone fragility. A thorough clinical and imaging evaluation is mandatory.

Orthopaedic aspects of child abuse

Increased awareness of child abuse has led to better understanding of this complex problem. However, the annual incidence of abuse is estimated at 15 to 42 cases per 1,000 children and appears to be increasing. More than 1 million children each year are the victims of substantiated abuse or neglect, and more than 1,200 children die each year as a result of abuse. The diagnosis of child abuse is seldom easy to make and requires a careful consideration of sociobehavioral factors and clinical findings. Because manifestations of physical abuse involve the entire child, a thorough history and a complete examination are essential. Fractures are the second most common presentation of physical abuse after skin lesions, and approximately one third of abused children will eventually be seen by an orthopaedic surgeon. Thus, it is essential that the orthopaedist have an understanding of the manifestations of physical abuse, to increase the likelihood of recognition and appropriate management. There is no pathognomonic fracture pattern in abuse. Rather, the age of the child, the overall injury pattern, the stated mechanism of injury, and pertinent psychosocial factors must all be considered in each case. Musculoskeletal injury patterns suggestive of nonaccidental injury include certain metaphyseal lesions in young children, multiple fractures in various stages of healing, posterior rib fractures, and long-bone fractures in children less than 2 years old. Skeletal surveys and bone scintigraphy with follow-up radiography may be of benefit in cases of suspected abuse of younger children. The differential diagnosis of abuse includes other conditions that may cause fractures, such as true accidental injury, osteogenesis imperfecta, and metabolic bone disease. Management should be multidisciplinary, with the key being recognition, because abused children have a substantial risk of repeated abuse and death.

Temporary brittle bone disease: a true entity?

Temporary brittle bone disease is a recently described phenotype of increased fracture susceptibility in the first year of life in which there are multiple unexplained fractures without evidence of other internal or external injury. Most child abuse experts do not accept the existence of temporary brittle bone disease and presume these cases are child abuse. The author reviewed 26 cases of infants with multiple unexplained fractures that fit the criteria of temporary brittle bone disease and studied nine of them with either computed tomography or radiographic bone density measurements. The results show a striking association between temporary brittle bone disease and decreased fetal movement, usually from intrauterine confinement, and low bone density measurements in eight of the nine infants. The association with decreased fetal movement and intrauterine confinement is in keeping with the mechanostat-mechanical load theory of bone formation. The author feels that temporary brittle bone disease is a real entity and that historical information related to decreased fetal movement or intrauterine confinement and the use of bone density measurements can be helpful in making this diagnosis.

Imaging of child abuse

Diagnostic imaging plays a fundamental role in the evaluation of suspected physical abuse. Judicious application of modern imaging techniques to cases of suspected abuse aids in early and accurate diagnosis, leading to appropriate measures to protect all family members at risk of serious injury.

Non-accidental injury or brittle bones

When a child presents with one or more unexplained fractures, non-accidental injury (NAI) should be considered in the differential diagnosis. This article reviews some of the other differential diagnoses, particularly osteogenesis imperfecta and the alleged "temporary brittle bone disease".

Non-accidental injury: confusion with temporary brittle bone disease and mild osteogenesis imperfecta

Accurate diagnosis of non-accidental injury (NAI) can be reached in the majority of cases by careful appraisal of the social and family history, combined with painstaking clinical roentgenographic and other imaging evaluations. Careful review of the scientific literature clearly indicates that collagen analysis to exclude mild forms of osteogenesis imperfecta, especially type IV, is recommended only in rare cases in which diagnosis of NAI remains in doubt even after thorough evaluation by experienced radiologists and/or other physicians. Until clinical research scientifically establishes the existence of temporary brittle bone disease, it should remain strictly a hypothetical entity and not an acceptable medical diagnosis.

Studies of collagen synthesis and structure in the differentiation of child abuse from osteogenesis imperfecta

OBJECTIVE

To determine whether analysis of collagen synthesized by dermal fibroblasts could identify children with osteogenesis imperfecta (OI) among those suspected to have been abused.

METHODS

We reviewed biochemical studies and clinical findings for all children who were referred to us to distinguish OI from abuse during a 4-year period.

RESULTS

Cells from 6 of 48 children tested to distinguish OI from abuse had biochemical evidence of OI. In five of the six children with abnormal results on collagen studies, clinical signs of OI in addition to fractures were present on examination by a physician familiar with the condition. In those five cases, the diagnosis of OI was strongly suspected.

CONCLUSIONS

OI can be diagnosed by biochemical studies in some cases of suspected abuse, but clinical evaluation by experienced physicians is usually sufficient to do so. When diagnostic uncertainty persists in cases of suspected child abuse, biochemical studies may be a useful adjunct, but routine biopsy for children suspected to have been abused is unwarranted.

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.