Biomedical subjects
Publications and source records attributed to L Sciorra.
The eukaryotic LAMMER protein kinase family is encoded by at least three loci in the human genome, designated CLK1, 2, and 3. We have mapped these loci to 2q33, 1q21, and 15q24, respectively, by fluorescent in situ hybridization. Additionally, a CLK2 pseudo-gene has been located to 7p15-21.
We have cloned a novel receptor tyrosine kinase that has an unusual ectodomain. The extracellular sequence consists of 416 amino acids and has none of the structural motifs that have been found in other receptor tyrosine kinases. The 150 amino acids in the amino terminus of the receptor is homologous to a putative phospholipid-binding sequence that is found also in other cell adhesion molecules such as the neuronal A5 antigen and coagulation factors V and VIII. The kinase domain has a short cytoplasmic tail and contains a short insert between subdomains I and II. The structure of this receptor kinase suggests that it belongs to a new family of receptors involved in cell-cell interactions. The cell adhesion kinase (Cak) is expressed at low levels in most adult tissues and expression is highest in the brain and lung. Using fluorescence in situ hybridization and interspecific backcross mapping, the Cak gene was localized to human chromosome 6 and mouse chromosome 17.
Although girls with Turner's syndrome (45,X) are not at risk for malignancy, patients with feminizing testicular syndrome with XY chromosome composition and patients with "mixed gonadal dysgenesis" are at risk for malignancy, and bilateral gonadectomy is performed. We have treated seven girls with "Turner-like" syndrome, who we believe are also "at risk" for development of malignancy and in whom gonadectomy should be performed. We present seven cases of phenotypically typical females, without sexual ambiguity, who presented with primary amenorrhea and short stature (5) and/or minor dysmorphic features (2). Chromosome analysis showed 45,X karyotype plus a fragment that we could not rule out as being part of a Y chromosome (in one patient a complete Y chromosome). In two patients, the fragment was subsequently positively identified as a Y, using a DNA probe. In view of the known high incidence of development of gonadoblastoma in the dysgenetic gonads of phenotypic females with a Y chromosome, bilateral gonadectomy was performed in these girls. Bilateral genital streaks with normal uterus and Fallopian tubes were found in all patients. In two patients unsuspected gonadoblastoma, without metastases, was found. In five cases, Leydig cells and tubular structures resembling rete testes were found, cells that are associated with Y-chromosomal tissue. We stress the need for complete chromosomal evaluation of phenotypically female patients with primary amenorrhea or features of Turner's syndrome. If a Y chromosome or the possibility of a Y chromosome cannot be excluded, gonadectomy should be performed because of the risk of malignancy.
A 17-year-old retarded male developed unilateral leg weakness with foot drop, pain, and incontinence. Workup disclosed a cauda equina tumor which, on surgical exploration, was demonstrated to merge with the conus medullaris. Pathological examination of the subtotally resected tumor led to a diagnosis of malignant ganglioglioma. Further evaluation of the patient documented marginal macro-orchidism, and chromosome studies showed fragile X. Since some neoplasms are known to be associated with chromosomal deletions and other abnormalities, we suggest that the occurrence of this tumor in this patient indicates a more than coincidental relationship between the two diagnoses.
Children with "pure" gonadal dysgenesis do not require abdominal explorations to remove their gonads, because the risk of development of malignancy is minimal. Children with "mixed" gonadal dysgenesis, who usually present with sexual ambiguity, need to have gonadectomy because of the high incidence of malignancy in these gonads. We present four children (three adolescents and one two year old) who presented with minimal somatic anomalies, who did not have sexual ambiguity. The prominent features were primary amenorrhea and short stature in the adolescents, and minor dysmorphic features in the small child. On the basis of these physical features, complete genetic evaluation was carried out, and a Y chromosome or an unidentifiable fragment was identified in all four cases. At exploration, bilateral genital streaks were found, and were removed. In addition to the usual microscopic features of the streaks, Leydig cells and tubular structures resembling rete testis were seen in all the gonads. In one gonad, a gonadoblastoma was found. Since this type of gonad is "at risk" for the development of gonadoblastoma, the need for complete genetic evaluation of all females with "Turner-like" chromosomal abnormalities, although phenotypically female, is emphasized. If a Y chromosome or any unusual fragment is identified, exploration should be carried out, and any gonad that is not a normal ovary should be removed.
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