Charles I. Scott

HRAS mutation analysis in Costello syndrome: Genotype and phenotype correlation

Costello syndrome is a rare condition comprising mental retardation, distinctive facial appearance, cardiovascular abnormalities (typically pulmonic stenosis, hypertrophic cardiomyopathy, and/or atrial tachycardia), tumor predisposition, and skin and musculoskeletal abnormalities. Recently mutations in HRAS were identified in 12 Japanese and Italian patients with clinical information available on 7 of the Japanese patients. To expand the molecular delineation of Costello syndrome, we performed mutation analysis in 34 North American and 6 European (total 40) patients with Costello syndrome, and detected missense mutations in HRAS in 33 (82.5%) patients. All mutations affected either codon 12 or 13 of the protein product, with G12S occurring in 30 (90.9%) patients of the mutation‐positive cases. In two patients, we found a mutation resulting in an alanine substitution in position 12 (G12A), and in one patient, we detected a novel mutation (G13C). Five different HRAS mutations have now been reported in Costello syndrome, however genotype–phenotype correlation remains incomplete.

Majewski osteodysplastic primordial dwarfism type II (MOPD II): Natural history and clinical findings

A description of the clinical features of Majewski osteodysplastic primordial dwarfism type II (MOPD II) is presented based on 58 affected individuals (27 from the literature and 31 previously unreported cases). The remarkable features of MOPD II are: severe intrauterine growth retardation (IUGR), severe postnatal growth retardation; relatively proportionate head size at birth which progresses to true and disproportionate microcephaly; progressive disproportion of the short stature secondary to shortening of the distal and middle segments of the limbs; a progressive bony dysplasia with metaphyseal changes in the limbs; epiphyseal delay; progressive loose‐jointedness with occasional dislocation or subluxation of the knees, radial heads, and hips; unusual facial features including a prominent nose, eyes which appear prominent in infancy and early childhood, ears which are proportionate, mildly dysplastic and usually missing the lobule; a high squeaky voice; abnormally, small, and often dysplastic or missing dentition; a pleasant, outgoing, sociable personality; and autosomal recessive inheritance. Far‐sightedness, scoliosis, unusual pigmentation, and truncal obesity often develop with time. Some individuals seem to have increased susceptibility to infections. A number of affected individuals have developed dilation of the CNS arteries variously described as aneurysms and Moya Moya disease. These vascular changes can be life threatening, even in early years because of rupture, CNS hemorrhage, and strokes. There is variability between affected individuals even within the same family.

Majewski Osteodysplastic Primordial Dwarfism Type II (MOPD II): Expanding the Vascular Phenotype

Majewski Osteodysplastic Primordial Dwarfism, Type II (MOPD II) is a rare, autosomal recessive disorder. Features include severe intrauterine growth retardation (IUGR), poor postnatal growth (adult stature approximately 100u2009cm), severe microcephaly, skeletal dysplasia, characteristic facial features, and normal or near normal intelligence. An Institutional Review Board (IRB) approved registry was created and currently follows 25 patients with a diagnosis of MOPD II. Based on previous studies, a neurovascular screening program was implemented and 13 (52%) of these patients have been found to have cerebral neurovascular abnormalities including moyamoya angiopathy and/or intracranial aneurysms. The typical moyamoya pathogenesis begins with vessel narrowing in the supraclinoid internal carotid artery, anterior cerebral (A1) or middle cerebral (M1) artery segments. The narrowing may predominate initially on one side, progresses to bilateral stenosis, with subsequent occlusion of the vessels and collateral formation. We present four patients who, on neurovascular screening, were found to have cerebrovascular changes. Two were asymptomatic, one presented with a severe headache and projectile vomiting related to a ruptured aneurysm, and one presented after an apparent decline in cognitive functioning. Analysis of the registry suggests screening for moyamoya disease be performed at the time of MOPD II diagnosis and at least every 12–18 months using MRA or computerized tomographic angiography (CTA). We believe this is imperative. If diagnosed early enough, re‐vascularization and aneurysm treatment in skilled hands can be performed safely and prevent or minimize long‐term sequelae in this population. Emergent evaluation is also needed when other neurologic or cardiac symptoms are present.

Short‐latency somatosensory evoked potentials in the management of patients with achondroplasia

Twenty-three patients with achondroplasia were evaluated using short-latency somatosensory evoked potentials (SEPs) of median and peroneal nerves. Abnormal studies were found in 61%. All patients with neurologic signs or symptoms had abnormal SEPs, with good correlation between SEP results and the level of the lesion determined clinically and radiographically. SEPs were abnormal in 44% of neurologically intact achondroplasts, several of whom had CTs confirming significant foramen magnum stenosis. SEPs are an important noninvasive means of evaluating patients with achondroplasia and are particularly valuable in children to document neurologic compromise before significant and perhaps irreversible clinical impairment develops.

Long-term neurological sequelae in achondroplasia

Two children with achondroplasia and neurologic sequelae secondary to foramen magnum compression were found to have syringomyelia. In one patient, the cyst was associated with a subependymal glioma. These findings suggest that foramen magnum stenosis may lead to irreversible spinal cord damage.

Lateral meningocele syndrome: Three new patients and review of the literature

One female and two male patients with multiple lateral meningoceles are presented. They do not have neurofibromatosis or Marfan syndrome and share findings with the two previously described patients with multiple lateral meningoceles. The original report by Lehman et al. [1977: J Pediatr 90:49-54] was titled familial osteosclerosis, because osteosclerosis was present in the proposita and her mother; the patient described by Philip et al. [1995: Clin Dysmorphol 4:347-351] also had increased bone density of the skull base and the sutures. Thickened calvaria were present in one of our patients; two had a prominent metopic suture. Other shared findings include multiple lateral meningoceles, Wormian bones, malar hypoplasia, downslanted palpebral fissures, a high narrow palate, and cryptorchidism in males. In addition, our patients showed ligamentous laxity, keloid formation, hypotonia, and developmental delay. A short umbilical cord was noted in two patients. One had a hypoplastic posterior arch of the atlas and an enlarged sella, as reported by Lehman et al. [1977]. Our patients appear to have the same syndrome as previously reported. We suggest it be called lateral meningocele syndrome, because of this unique finding.

Cervical Spinal Stenosis in Metatropic Dysplasia

Abstract: Metatropic dysplasia is a rare skeletal dysplasia characterized by rapid collapse of the thoracolumbar spine into kyphoscoliosis. Other spinal anomalies associated with metatropic dysplasia include odontoid hypoplasia and atlantoaxial instability leading to cervical myelopathy. Children with metatropic dysplasia evaluated at our institution for spinal deformity showed evidence of cervical stenosis with or without associated cord compression. Magnetic resonance imaging was found to demonstrate these changes. The association of cervical spinal stenosis and metatropic dysplasia has not been previously described. This has significant treatment implications, because decompression over the stenotic segments should be considered in conjunction with spinal fusion for treatment of odontoid hypoplasia or atlantoaxial instability. A retrospective review of 13 cases of metatropic dysplasia was performed. Despite the challenges provided by this patient population, the chance to halt or reverse neurological dysfunction and improve deformity necessitates prompt surgical intervention.

Progressive Neurologic Deterioration and Renal Failure Due to Storage of Glutamyl Ribose-5-Phosphate

A six-year-old boy presented with a history of seizures, progressive neurologic deterioration, and proteinuria. Physical examination revealed mildly coarse facies, failure to thrive, generalized hypotonia with muscle wasting, and optic atrophy; there was no organomegaly. The family history suggested an X-linked recessive inheritance. The electroencephalogram, electroretinogram, evoked potentials, and computed axial tomography of the brain were abnormal. Urine oligosaccharide chromatography, urine amino acids and organic acids, and results of leukocyte and fibroblast lysosomal-enzyme assays for the known storage diseases were normal; however, conjunctival and renal biopsy specimens contained enlarged lysosomes on electron microscopy. The patient had progressive neurologic deterioration and died of renal failure at eight years of age. A compound identified as glutamyl ribose-5-phosphate was purified from the brain (0.96 mumol per gram, wet weight) and kidney (0.60 mumol per gram, wet weight). This compound is the linkage group in ADP-ribosylation of proteins, an important regulatory process in gene expression and DNA repair. We believe this new disorder represents a glycoproteinosis that results in the cytoplasmic storage of glutamyl ribose-5-phosphate.

Spondyloepimetaphyseal dysplasia with joint laxity (SEMDJL)

Spondyloepimetaphyseal dysplasia with joint laxity (SEMDJL) is a distinctive form of skeletal dysplasia characterized by severe dwarfism, generalized articular hypermobility, and progressive spinal malalignment. We report on a patient with SEMDJL, who presented with all the characteristic orthopedic manifestations of the disorder, required multiple operative procedures, and has the longest reported follow‐up and survival into adulthood with a favorable outcome. We describe all the clinical and radiographic findings that can allow an early diagnosis of this type of skeletal dysplasia, which can lead to profound disability with potentially lethal spinal and pulmonary complications in early childhood. In view of the severe clinical and genetic implications, diagnostic precision is of vital importance, particularly since the disorder is currently believed to be more common than initially reported.

Extending the spectrum of distal arthrogryposis

We describe a mother and son with multiple, non-progressive, congenital contractures, camptodactyly and absent flexion creases, expressionless face, blepharophimosis, microstomia, and short stature. Although these cases share similarities with the autosomal-recessive Schwartz-Jampel and Marden-Walker syndromes, they have a different mode of inheritance and lack myotonia, one of the most characteristic findings of the Schwartz-Jampel syndrome. Our cases most closely resemble those previously reported as distal arthrogryposis type IIb, although in our patients the proximal joints are severely affected and extraocular involvement is absent. Hearing loss is present in one and cleft palate in the other of our patients; these findings were previously described in arthrogryposis syndromes other than type IIb. We suggest extending the spectrum of distal arthrogryposis to include these manifestations, since there appears to be significantly overlap between the different syndromes.