1/202. Respiratory sinus arrhythmia of brainstem lesions. In this pilot study we investigated the hypothesis that intrinsic and extrinsic brainstem lesions situated within the pontomedullary region would effect the integrity of respiratory sinus arrhythmia. The study sample consisted of three patients with anatomic brainstem abnormalities associated with isolated Chiari I malformation, Chiari II malformation with syringobulbia, and achondroplasia with cervicomedullary compression. They were compared to an age- and sex-matched control group of nine patients. Each subject's electrocardiogram was recorded in a quiet room and digitized by a personal computer during five 1-minute periods. R-R intervals within each 1-minute period were converted to heart rate in 120 successive 0.5-second intervals. The resultant heartrate time series was converted to its underlying frequency composition by a fast Fourier transform and averaged across minutes. Respiratory sinus arrhythmia was defined as the variability in the time series over a frequency range (0.096 to 0.48 Hz) corresponding to a range of respiratory rates from 6 to 30 breaths per minute. Analysis revealed a significant reduction in respiratory sinus arrhythmia (P < .05), defined as the summated area under the curve, with a mean for controls of 35.42 /-28.13 SD and for subjects of 17.20 /-11.50 SD. There was a gradient of abnormality noted, with the mildest deviation in respiratory sinus arrhythmia for the patient with isolated Chiari I malformation and maximum deviation seen in the patient with extrinsic cervicomedullary compression. ( info) |
2/202. achondroplasia-hypochondroplasia complex in a newborn infant. We describe the case of an 8-month-old girl with achondroplasia-hypochondroplasia complex. The diagnosis was suggested antenatally when obstetrical ultrasonography at 27 weeks of gestation showed short limbs, small chest, and macrocephaly. The father has achondroplasia due to the common G1138A (G380R) mutation in the fibroblast growth factor receptor 3 (FGFR3) gene, while the mother has hypochondroplasia due to the C1620G (N450K) mutation in the FGFR3 gene. Neither had had genetic counseling or molecular testing prior to the pregnancy. Antenatal ultrasound study at 29 weeks of gestation showed a large head, very short limbs, and a small chest; the findings were more severe than in achondroplasia or hypochondroplasia alone. The patient was born by cesarean section at 37 weeks of gestation and had rhizomelic shortness of limbs with excess skin creases, large head, and small chest, diagnostic of achondroplasia. Radiographs showed shortness of the long bones and flaring of the metaphyses. She had mild hypoplasia of lungs. Molecular testing showed both the G1138A and the C1620G mutations in FGFR3, confirming the diagnosis of achondroplasia-hypochondroplasia complex. At 8 months, she has disproportionate shortness of the long bones and a large head with frontal bossing and a depressed nasal bridge. Her chest remains small, and she is on home oxygen at times of respiratory stress. She has a large gibbus. She is delayed in her motor development and has significant head lag. To our knowledge, there is only one previously published report of achondroplasia-hypochondroplasia complex. ( info) |
3/202. Compound heterozygosity for the achondroplasia-hypochondroplasia FGFR3 mutations: prenatal diagnosis and postnatal outcome. We report on a male newborn infant, a compound carrier of heterozygous mutations in the FGFR3 gene causing achondroplasia and hypochondroplasia. The mother has achondroplasia and carries the common G1138 (G380R) mutation in the FGFR3 gene; the father has hypochondroplasia due to the C1620A (N540K) mutation in the same gene. The fetus was found to carry both mutations diagnosed prenatally by amniocentesis at 17.6 weeks of gestation, following maternal serum screening which showed an increased risk for down syndrome (1:337). Detailed fetal ultrasound studies showed a large head, short limbs, and a small chest at 22 weeks of gestation. The changes were more severe than those of either achondroplasia or hypochondroplasia. The patient was born by cesarean section at 38 weeks of gestation and had rhizomelic shortness of the upper and lower limbs with excess skin folds, large head, enlarged fontanelles, frontal bossing, lumbar gibbus, trident position of the fingers, and a narrow chest with a horizontal line of demarcation at the narrowest area of the chest. Skeletal radiographs showed shortness of the long bones and flare of metaphyses. He had respiratory difficulties and was treated with nasal prongs. seizures developed on day 2 of life and recurred on day 9 and responded to treatment with phenobarbital. brain computed tomographic scan showed possible grey matter heterotopia, partial agenesis of the corpus callosum, and cortical dysplasia. To our knowledge, there are only two previously published cases of compound heterozygous achondroplasia-hypochondroplasia patients. The diagnosis was confirmed by dna mutation analysis of the FGFR3 gene in both cases. ( info) |
4/202. Jugular bulb dehiscence in achondroplasia. Jugular bulb dehiscence--complete absence of a roof over the jugular bulb--is a rare malformation, probably present in <<< 1% of the general pediatric population. Of 126 children with achondroplasia evaluated in the Midwest Regional Bone Dysplasia Clinic, four and probably five, were identified as having such dehiscence (at least 3.2% of the children assessed). Identifying this increased incidence in achondroplasia is of some clinical relevance, particularly including risk of difficult to control bleeding at myringotomy. It may also present as otherwise unexplained hearing loss, tinnitus and self audible bruits in these children. ( info) |
5/202. Fatal laryngeal injury in an achondroplastic dwarf secondary to airbag deployment. We report the case of an unrestrained driver with achondroplastic dwarfism who suffered a fatal anterior neck injury when her airbag deployed as she rear-ended another vehicle at 30-40 mph. Her short stature and short limbs required her to sit within a handbreadth of the steering wheel, which probably allowed the airbag or airbag cover to strike her neck as it opened. This is the first reported case of fatal injury to a driver with achondroplastic dwarfism. ( info) |
6/202. Kyphomelic dysplasia: clinical and radiologic long-term follow-up of one case and review of the literature. The authors describe the 17-year follow-up of the (to their knowledge) only adult and only female patient affected with kyphomelic dysplasia so far described in the literature, with assessment of the phenotypic, orthopedic, and radiologic progression of this syndrome. ( info) |
7/202. Whole body bone mass and body composition in a girl with achondroplasia, at ages 9 through 12. A 9-yr-old white female with achondroplasia was one of a group of 773 children who were recruited for a study of the accumulation of whole body skeletal mass during four annual measurements. Measurements of bone, fat, and lean mass were obtained with a Hologic 1000W instrument. The following variables are used to compare the subject with the 130 healthy white girls who participated in the study: bone mineral content (BMC), bone mineral density (BMD), and bone mineral apparent density (BMAD). Ratios of BMC to weight or BMC to height, and BMD to weight or height, were also calculated. We found that the BMC of the subject was lower when compared to the reference group, but the ratios of BMC to weight or BMC to height were similar in both. BMD was also lower in the patient, but, when expressed in relation to height and weight, the ratios were similar or slightly higher in the case. BMAD was higher in the subject with achondroplasia at all ages. The subject had a lower percentage fat and higher percentage lean mass than the reference children. We conclude that the accumulation of bone mass in this subject with achondroplasia is appropriate for her reduced body size. ( info) |
8/202. Kyphomelic dysplasia: a report of a family with an autosomal dominant pattern. Kyphomelic dysplasia (KD) is a rare autosomal recessive entity characterized by shortening and bowing of the limbs, skin dimples, abnormalities of methaphysis and ribs, a short trunk, a narrow thorax, neonatal respiratory distress, platyspondyly, and facial dysceptism with micrognathia, midfacial hypoplasia, and a broad nasal bridge. Some children die in early infancy. The survivors show normal hands, feet, cranium and psychomotor development. The condition varies in severity. The facial features and bowing improve during childhood, and stature remains short during adulthood. We report here a family with KD inherited as an autosomal dominant trait, which appears to be less severe than the autosomal recessive form, without facial and vertebral a favorable outcome and with involvement and final short stature. ( info) |
9/202. Prenatal sonographic diagnosis of hypochondroplasia in a high-risk fetus. Hypochondroplasia (HCH) is caused by mutations in the fibroblast growth factor receptor type 3 (FGFR 3). prenatal diagnosis of HCH based exclusively on the sonographic measurements of the fetal skeleton is difficult and has not been reported. We describe a newborn infant with HCH who was born to a mother with achondroplasia (ACH) and a father with HCH. Serial sonographic measurements were recorded from 16 weeks of gestation. All measurements remained normal up to 22 weeks of gestation. At 25 weeks of gestation, the long bones began to appear shorter than expected for gestational age, while the head measurements (biparietal diameter and head circumference) remained normal. The measurements were sufficiently different to distinguish from findings in normal and achondroplastic fetuses. Our findings suggest that it is possible to distinguish the normal fetus from a fetus affected with HCH and to distinguish HCH and ACH from each other based on the sonographic measurements alone. To our knowledge, this is the first report of longitudinal sonographic measurements of HCH in the second and third trimesters. ( info) |
10/202. achondroplasia and cervicomedullary compression: prospective evaluation and surgical treatment. The association between sudden death and cervicomedullary compression in infants with achondroplasia has been well described. Prospective clinical and imaging evaluations have been recommended to identify those infants with achondroplasia who are at risk of dying suddenly from respiratory arrest secondary to unrecognized cervicomedullary compression. Since 1988, we have prospectively evaluated 11 infants (average age 13 weeks) with achondroplasia who were asymptomatic for cervicomedullary compression on initial clinical evaluation. Craniocervical magnetic resonance imaging (MRI) findings included narrowing of the foramen magnum, effacement of the subarachnoid spaces at the cervicomedullary junction, abnormal intrinsic cord signal intensity and mild to moderate ventriculomegaly. Two patients with severe cord compression underwent immediate decompression. Two patients developed opisthotonic posturing within 3 months of evaluation and underwent foramen magnum decompression, including suboccipital craniectomy and atlantal laminectomy. Surgery in all cases revealed forward extension of the squamous portion of the occipital bone, thickened posterior rim of the foramen magnum and a dense fibrotic epidural band. There were no complications from surgery. Seven patients did not require surgery and were followed closely. All 11 patients remain asymptomatic at follow-up (mean 4.6 years; range 16 months to 7.3 years), and no patient has required a diversionary shunt procedure. The results of this prospective study confirm that early clinical and MRI evaluations are necessary to determine whether infants with achondroplasia have cervicomedullary compression. With early recognition, an immediate decompression can be performed safely to avoid serious complications associated with cervicomedullary compression, including sudden death. copyright copyright 1999 S. Karger AG, Basel ( info) |