The effect of height, weight and head circumference on gross motor development in achondroplasia.

PURPOSE: This study aimed to investigate whether height, weight, head circumference and/or relationships between these factors are associated with gross motor milestone acquisition in children with achondroplasia. METHOD: Population-based data regarding timing of major gross motor milestones up to 5 years were correlated with height, weight and head circumference at birth and 12 months in 48 children with achondroplasia born in Australia and New Zealand between 2000 and 2009. RESULTS: Although as a group children with achondroplasia showed delayed gross motor skill acquisition, within group differences in height, weight or head circumference did not appear to influence timing of gross motor skills before 5 years. The exception was lie to sit transitioning, which appears likely to occur earlier if the child is taller and heavier at 12 months, and later if the child has significant head-to-body disproportion. CONCLUSIONS: This is the first study to investigate the relationship between common musculoskeletal impairments associated with achondroplasia and timing of gross motor achievement. Identification of the musculoskeletal factors that exacerbate delays in transitioning from lying to sitting will assist clinicians to provide more proactive assessment, advice and intervention regarding motor skill acquisition for this population.

Development in children with achondroplasia: a prospective clinical cohort study.

AIM: Achondroplasia is characterized by delays in the development of communication and motor skills. While previously reported developmental profiles exist across gross motor, fine motor, feeding, and communication skills, there has been no prospective study of development across multiple areas simultaneously. METHOD: This Australasian population-based study utilized a prospective questionnaire to quantify developmental data for skills in children born from 2000 to 2009. Forty-eight families from Australia and New Zealand were asked to report every 3 months on their child's attainment of 41 milestones. Results include reference to previously available prospective information. RESULTS: Information from questionnaires was used to develop an achondroplasia-specific developmental recording form. The 25th, 50th, 75th, and 90th centiles were plotted to offer clear guidelines for development across gross motor, fine motor, feeding, and communication skills in children with achondroplasia. INTERPRETATIONS: Consistent with results from previous research, children with achondroplasia are delayed in development of gross motor and ambulatory skills. Young children with achondroplasia demonstrate a number of unique movement strategies that appear compensatory for the biomechanical changes. While delays were seen in development of later communication items, there were fewer delays seen across development of early communication, fine motor, and feeding skills.

Medical management of children with achondroplasia: evaluation of an Australasian cohort aged 0-5 years.

AIMS: Achondroplasia is the most common form of osteochondrodysplasia and is associated with a number of life-threatening complications. The complexity of the condition led to the development of Heath Supervision Guidelines published by the American Academy of Pediatrics in 1995 and revised in 2005. There remains limited population-based information on utilisation of medical and therapy services for children with achondroplasia. Increased information regarding use of these services will assist in future service development. METHODS: Data regarding frequency and timing of medical and allied health consultations, investigations and interventions were collected from 53 Australasian families via questionnaire, based on recommendations of the Health Supervision Guidelines, an expert reference group and literature review. RESULTS: Rates varied with age for medical consultations (geneticist, paediatric rehabilitation physician/paediatrician, respiratory physician, orthopaedic consultant, neurologist, neurosurgeon), medical investigations (sleep study, magnetic resonance imaging/computed tomography), operative procedures (brain-stem decompression, tonsillectomy/adenoidectomy, shunt insertion, shunt revision and insertion of grommets) and allied health consultations (physiotherapist, occupational therapist, speech pathologist, dietician and orthotist). CONCLUSIONS: Access to geneticists and paediatricians within the first year is high as recommended by the 2005 American Academy of Pediatrics guidelines. Utilisation of craniocervical magnetic resonance imaging/computed tomography, polysomnography studies and formal speech review appears low, reflecting more emphasis on clinical monitoring for cervical cord compression and disordered sleep breathing as well as possible difficulties in accessing services for polysomnography and speech pathology. Grommet insertion, tonsillectomy/adenoidectomy and cervicomedullary decompression rates are similar to results reported previously. Over half of the children accessed physiotherapy and/or occupational therapy services, warranting consideration of these professionals in future guideline recommendations.

Functional performance in young Australian children with achondroplasia.

AIM: The aim of this study was to determine population-specific developmental milestones for independence in self-care, mobility, and social cognitive skills in children with achondroplasia, the most common skeletal dysplasia. METHODS: Population-based recruitment from October 2008 to October 2010 identified 44 Australian children with achondroplasia aged 3 to 7 years. Consenting parents of 35 children (16 males, 19 females 14 aged 3y; 12 aged 5y; nine aged 7y) reported their child's self-care, mobility, and social cognition function using the Functional Independence Measure for Children (WeeFIM-II) at the ages of 3 (n=14), 5 (n=12), or 7 (n=9) years. Children were excluded from the study if they had an additional neurological or musculoskeletal condition. RESULTS: Functioning improved in children with achondroplasia between the ages of 3 and 5 years, but not subsequently. Milestones in the achondroplasia group were delayed across all ages and domains compared with normative reference data. Children with achondroplasia required greater caregiver assistance for self-care and mobility skills than typically developing children based on normative data. Social cognition appeared to be an area of relative strength. INTERPRETATION: Children up to 7 years of age with achondroplasia show delayed milestone acquisition and a greater need for caregiver assistance for all domains. As functional delays are likely to be related to common musculoskeletal impairments associated with achondroplasia, access to physiotherapists, occupational therapists, and speech and language pathologists skilled in achondroplasia management may assist children and families to become more independent, particularly around the time of starting school.

Respiratory events and obstructive sleep apnea in children with achondroplasia: investigation and treatment outcomes.

PURPOSE: We report aspects of sleep-disordered breathing in a cohort of achondroplastic children who attended our hospital. METHODS: A retrospective chart review was conducted for a 15-year period to further evaluate the diagnosis and treatment of sleep-disordered breathing in children with achondroplasia. RESULTS: A review of the medical records was undertaken for 46 children (63%, mean age 3.9 years) with achondroplasia that had overnight polysomnography. Among them, 25 (54.3%) had obstructive sleep apnea (OSA). For 19 out of 46 patients (follow-up rate, 41.3%) with a mean follow-up of 31.3 months (range, 3 month to 11 years), 13 had undergone adenotonsillectomy, while nine were treated with continuous positive airway pressure. CONCLUSIONS: Prospective evaluation of our clinic population confirms a high incidence of SDB in achondroplastic children. OSA has been linked to raise intracranial pressure as well as neurocognitive deficits in children and we hypothesize that associations between neurological and respiratory abnormalities in this disorder are a consequence of the early onset of associated respiratory, rather than the neurological complications.

The natural history and osteodystrophy of mucolipidosis types II and III.

AIM: To assess the natural history and impact of the secondary bone disease observed in patients with mucolipidosis (ML) II and III. METHODS: Affected children and adults were ascertained from clinical genetics units around Australia and New Zealand. Diagnoses were confirmed by the National Referral Laboratory in Adelaide. The study encompassed all patients ascertained between 1975 and 2005. Data focussing on biochemical parameters at diagnosis, and longitudinal radiographic findings were sought for each patient. Where feasible, patients underwent clinical review and examination. Examinations included skeletal survey, bone densitometry, and measurement of serum and urine markers of bone metabolism. In a subset of patients, functional assessment using the Pediatric Evaluation and Disability Inventory (PEDI) and molecular analysis of GNPTAB were performed. RESULTS: Twenty-five patients with mucolipidosis were ascertained over a 30-year period. Morbidity and functional outcomes on living patients were described. Serum calcium and phosphate were normal. All, but one patient, had normal alkaline phosphatase. Serum osteocalcin and urine deoxypyridinoline/creatinine were elevated. Two radiological patterns were observed (i) transient neonatal hyperparathyroidism in infants with ML II and (ii) progressive osteodystrophy in patients with ML intermediate and ML III. Molecular analyses of GNPTAB in nine subjects are reported. CONCLUSION: ML is characterised by a progressive bone and mineral disorder which we describe as the 'osteodystrophy of mucolipidosis'. The clinical and radiographic features of this osteodystrophy are consistent with a syndrome of 'pseudohyperparathyroidism'. Much of the progressive skeletal and joint pathology is attributable to this bone disorder.

Developmental milestones in infants and young Australasian children with achondroplasia.

BACKGROUND: Achondroplasia, the most common form of chondrodysplasia (inherited skeletal dysplasia), is characterized by a significant delay in the development of communication and motor skills, particularly during the first 2 years. Although some information regarding timing of development for children with achondroplasia is available, no study has evaluated simultaneously the pattern of skill development across multiple key developmental areas. METHOD: This study used a retrospective questionnaire to quantify developmental data on milestone achievement. Twenty families of children with achondroplasia throughout Australia and New Zealand were asked to document age of acquisition for 41 gross motor, fine motor, and communication and feeding milestones. More than one half of the items assessed were milestones identified in the Australian State Government Personal Health Record Books. The results are compared with previously available information regarding development of motor skills by a cohort of American children with achondroplasia. RESULTS: Although the results support previously reported delays in gross motor and communication skill development, fine motor development does not seem to be as delayed as previously suggested. Information on development of self-feeding skills is presented for the first time and occurs later in this group than the typically developing population. We describe 2 distinctive and previously unreported methods of transitioning between static positions commonly used by children with achondroplasia. CONCLUSION: Delays were reported across gross motor and communication and feeding skills but were not observed during development of fine motor skills. Additional information is also offered regarding a variety of unusual movement strategies demonstrated by young children with achondroplasia.