Primary motor cortex and ipsilateral control: a TMS study.

In this transcranial magnetic stimulation study, we assessed motor cortex excitability in the resting hemisphere while the homologous side was active during a voluntary unimanual task. Data acquired from left- and right-handers showed that cortical excitability varied as a function of isometric task demands and hand dominance. In particular, facilitation of the motor-evoked potentials was observed across task requirements in left-handers, independent of which hemisphere was active. In right-handers, facilitation was present when the right hemisphere was active whereas this effect was largely reduced when the left hemisphere was active, suggesting pronounced inhibitory interactions from the left (dominant) to the right (non-dominant) hemisphere. The distinct scaling of motor cortex excitability indicates the importance of the left hemisphere in guiding manual control in right-handers whereas both hemispheres are functionally relevant in left-handers. Overall, the results underline the asymmetrical organization of the motor system in right-handers with an important role of the dominant hemisphere whereas symmetrical functional abilities of both hemispheres characterize left-handers.

Rubinstein-Taybi syndrome and psychiatric disorders.

Major psychiatric disorders have a complex genetic aetiology. The study of psychiatric phenotypes in individuals with malformation syndromes may allow one to search for the genes that confer an increased risk for the same psychiatric disorders in the general population. The present authors report on the psychiatric evaluations of 13 patients with classic or incomplete features of Rubinstein-Taybi syndrome (RTS), a multiple congenital anomaly syndrome mapped to 16p13.3, whose psychiatric diagnoses fell within a consistent spectrum, suggesting a possible relationship between RTS and these psychiatric disorders. The diagnoses clustered into mood disorders and the tic/obsessive compulsive disorder (OCD) spectrum; all tic/OCD diagnoses occurred in patients with classical RTS. It was of interest that neuroleptic-induced movement disorders and neuroleptic malignant syndrome were common. While no conclusions can be drawn about the prevalence of psychiatric disorders in RTS, the pattern of psychiatric diagnoses in these patients appear non-random, and the occurrence and severity of neuroleptic side-effects is striking. Given the suspected relationship of these complications with the serotonergic and dopaminergic systems, the present authors suggest that the gene locus for RTS should be investigated for genes related to the regulation of these neurotransmitters.

Acute lymphoblastic leukemia in a child with the CHIME neuroectodermal dysplasia syndrome.

The "CHIME" syndrome (MIM#280000) is a rare neuroectodermal disorder comprised of Colobomas of the eye, Heart defects, Ichthyosiform dermatosis, Mental retardation, and Ear defects. We report on the sixth child with this syndrome and the first of these to develop acute lymphoblastic leukemia at age 4 1/2 years. Her major problems included a migratory ichthyosiform dermatosis, multiple skin infections and infestations, bilateral retinal coloboma, developmental delay, seizures, infantile macrosomia, facial anomalies, a duplicated renal collecting system, and conductive hearing loss. Histologic examination of the skin demonstrated findings of an epidermal nevus with deep rete pegs, hyperkeratosis, and a markedly increased granular layer. The cause of the CHIME syndrome is unknown, but the disorder is easily recognized because of the striking phenotype. The diagnosis is important to make because of the potential for associated congenital heart disease, neurologic compromise, possible autosomal recessive inheritance, and possible association with malignancy.

Standard curves of chest circumference in achondroplasia and the relationship of chest circumference to respiratory problems.

Several pathogenetic factors, alone or in combination, may contribute to the increased frequency of respiratory complications in achondroplasia. It has been suggested that relatively small chest circumference sometimes may contribute. However, there are no published curves of chest circumference for age in achondroplasia with which to compare patients. Nor are there data relating chest circumference to overall size in achondroplasia. We present curves of chest circumference for males and females with achondroplasia from birth through age 7 years. Additional curves for chest circumference against height are also provided. Finally, we report some preliminary data regarding the possible association of chest size with respiratory signs and symptoms.

Two craniosynostotic patients with 11q deletions, and review of 48 cases.

Many chromosomal abnormalities have craniofacial manifestations. One such abnormality, partial monosomy of chromosome 11q, is associated with metopic synostosis and resultant trigonocephaly. We reviewed 48 published cases of 11q deletions and translocations. Eighty percent were associated with abnormal head shape. Also commonly found were hypertelorism, ptosis of the eyelids, wide or low nasal bridge, apparently low-set malformed ears, down-turned mouth, micro/retrognathia, digital and cardiac anomalies, and psychomotor retardation. We report on two patients referred for abnormal head shape. The first case had brachycephaly, flat occiput, hypertelorism, and maxillary hypoplasia. Karyotype was 46,XY,del(11)(q24.1-->qter). The second patient had trigonocephaly, hypotelorism, posteriorly angulated ears, horizontal crease below his lower lip, syndactyly, shawl scrotum, cryptorchidism, and inguinal hernias. Karyotype showed partial trisomy of chromosome 4q as well as partial monosomy of 11q [46,XY,11,+der(11)t(4;11) (q31.3;q25)], a combination not previously reported. Deletions of 11q appear to produce a wide spectrum of abnormalities.

Short tandem repeat polymorphism linkage studies in a new family with X-linked mental retardation (MRX20).

A family with X-linked recessive mental retardation (XLMR) without other obvious manifestations (MRX20) was studied with 14 short tandem repeat polymorphism (STRP) markers. Two-point lod scores above 3 were obtained with DXS1003, DXYS1, DXS3, and DXS458. A multipoint lod score of 4.25 was obtained with peak at DXS1003. Recombination events identify a 55.6 cM interval between DXS1068 and DXS454, while a one unit support interval identifies 40 cM between MAOA and DXS458.

Saethre-Chotzen syndrome with familial translocation at chromosome 7p22.

Chromosome analysis of a male infant and his mother with Saethre-Chotzen syndrome demonstrated an apparently balanced translocation, t(2;7)(p23;p22). This association lends support to localization of the gene for Saethre-Chotzen syndrome to the 7p2 region and supports further involvement of gene(s) in the 7p22 region.

Further delineation of spondylo-meta-epiphyseal dysplasia, short limb-abnormal calcification type, with emphasis on diagnostic features.

Further delineation of a generalized bone dysplasia which we call spondylo-meta-epiphyseal dysplasia, short limb-abnormal calcification type is presented. This dwarfing condition has several serious complications, with the most common cause of death being spinal cord damage secondary to atlantoaxial instability. It is a heritable condition with an autosomal recessive mode of transmission. Radiologic diagnostic criteria are developed on the basis of studies in 8 patients with the oldest being between 4 and 5 years old. The condition is clinically and radiographically apparent neonatally or in early infancy, and it is probable that all or almost all affected individuals will come to medical attention in the age range screened by this study.

Management of major craniofacial anomalies: a pediatric perspective.

Ethical decision-making regarding complex congenital anomalies has evolved along with improvements in neonatal medical and surgical care, but also reflects a changed medical and social environment. The current process is complex and cumbersome, with no guarantee of consensus, and frequently leads to indecision and disagreement. Improvement of the process will require continued professional education, as well as better reconciliation of areas of ambivalence among professionals, families, and society.

Growth of the foramen magnum in achondroplasia.

Foramen magnum growth curves in achondroplasia and in the general population are presented. The achondroplastic foramen magnum is small at birth, and during the first year it has a severely impaired rate of growth especially in the transverse dimension. This markedly diminished growth results not only from abnormal endochondral bone growth but also because of abnormal placement and premature fusion of the synchondroses. Evaluation of the foramen magnum in achondroplasia should address absolute size of the transverse and sagittal dimensions, shape, and growth centers to determine growth potential of this area.

Chemotherapy-associated eccrine hidradenitis: neutrophilic eccrine hidradenitis reevaluated: the role of neutrophilic infiltration.

Two cases of chemotherapy-associated eccrine hidradenitis are presented. Previous cases have been labeled "neutrophilic eccrine hidradenitis" (NEH). Both cases reported herein involve neutropenic patients and are notable for the absence of neutrophils on histologic examination. Oncologists need to be aware of this newly described process, and this rash must be added to the differential diagnosis of the neutropenic oncology patient. The role of neutrophils in this disorder is discussed, and a new term, "chemotherapy-associated eccrine hidradenitis," is suggested for this unusual process.

Pediatric patients with achondroplasia: CT evaluation of the craniocervical junction.

Twenty-six patients (4 months to 6 years old) with achondroplasia complicated by sleep apnea and/or other neurologic manifestations underwent plain computed tomography (CT) of the craniocervical junction; six also underwent CT myelography. For objectification, multiplanar reconstruction was used to complement axial plane measurements by providing coronal and sagittal measurements; multiplanar reconstruction also improved perception of the longitudinal relationships between the brain stem and subarachnoid space. A narrow subarachnoid space was found in all 26 patients; marked cord compression was present in nine, six of whom underwent CT myelography. These six had marked focal obliteration of the subarachnoid space on both plain CT and CT myelography. Since the subarachnoid space immediately above and below the craniocervical junction is normally capacious, when marked constriction was present, no additional information could have been gained from CT myelography. Thus, plain CT was shown to be sufficient for surgical planning (suboccipital decompression) in nine patients with cord compression due to achondroplasia.

Cervicomedullary compression in young patients with achondroplasia: value of comprehensive neurologic and respiratory evaluation.

We studied prospectively 26 young patients with achondroplasia to test two hypotheses: that respiratory problems may be the result of occult spinal cord compression, and that achondroplastic patients with cord compression might have occult respiratory abnormalities. Respiratory abnormalities were present in 85%, the majority caused by a primary problem of the pulmonary system, such as small thoracic cage or obstructed airway. Three patients had hypoxemia, recurrent cyanotic spells, and episodes of respiratory distress explainable only by cervicomedullary cord compression; in each patient, respiratory problems were alleviated by decompressive surgery. Another six patients with cervicomedullary compression had, in addition, at least one primary pulmonary cause of respiratory problems. After decompressive surgery the respiratory problems improved in three and were unchanged in three. Reconstructed sagittal CT images proved the most sensitive technique for detecting craniocervical stenosis as a cause of cervicomedullary cord compression, although some degree of stenosis was present in nearly all of the patients.