Biomedical subjects
Publications and source records attributed to P L Townes.
We report 2 cases of concordant prune belly syndrome occurring in monozygotic twins. In addition to suggesting a genetic basis for this disease, our 12-year follow-up of these cases illustrates that these patients with an otherwise poor prognosis can have normal growth, development, and renal function with appropriate treatment.
We have identified a novel gene, transducin (beta)-like 1 (TBL1), in the Xp22.3 genomic region, that shows high homology with members of the WD-40-repeat protein family. The gene contains 18 exons spanning approximately 150 kb of the genomic region adjacent to the ocular albinism gene (OA1) on the telomeric side. However, unlike OA1, TBL1 is transcribed from telomere to centromere. Northern analysis indicates that TBL1 is ubiquitously expressed, with two transcripts of approximately 2.1 kb and 6.0 kb. The open reading frame encodes a 526-amino acid protein, which shows the presence of six beta-transducin repeats (WD-40 motif) in the C-terminal domain. The homology with known beta-subunits of G proteins and other WD-40-repeat containing proteins is restricted to the WD-40 motif. Genomic analysis revealed that the gene is either partly or entirely deleted in patients carrying Xp22.3 terminal deletions. The complexity of the contiguous gene-syndrome phenotype shared by these patients depends on the number of known disease genes involved in the deletions. Interestingly, one patient carrying a microinterstitial deletion involving the 3' portion of both TBL1 and OA1 shows the OA1 phenotype associated with X-linked late-onset sensorineural deafness. We postulate an involvement of TBL1 in the pathogenesis of the ocular albinism with late-onset sensorineural deafness phenotype.
OBJECTIVES: This study sought to find an association between dilated cardiomyopathy and limb-girdle muscular dystrophy. BACKGROUND: Cardiomyopathy has been seen in various neuromuscular disorders, but it has not been recognized to be associated with limb-girdle muscular dystrophy. METHODS: We investigated three sisters with well documented limb-girdle dystrophy and congestive heart failure by the 3rd decade of life. All underwent noninvasive evaluation of left ventricular systolic function by both echocardiography and radionuclide scanning, and one also had cardiac catheterization. Deoxyribonucleic acid (DNA) linkage analysis was performed in these affected subjects and in the unaffected family members, and DNA was extracted from mononuclear cells with primer sequences for three chromosome 13q microsatellite markers. RESULTS: The parents had no evidence of clinical disease, but all three sisters had echocardiographic evidence of dilated cardiomyopathy. The sister with additional evidence of left ventricular dysfunction of cardiac catheterization had no coronary artery disease. The affected subjects had the same paternal allele for three potential markers of limb-girdle muscular dystrophy but different maternal alleles. The very small family size did not permit statistical confirmation or refutation of linkage for chromosome 13q markers. CONCLUSIONS: Demonstrable cardiomyopathy accompanying limb-girdle muscular dystrophy and its probable genetic associations require continued investigation by anticipating the cardiomyopathy in limb-girdle muscular dystrophy.
We report the variation in vivo and instability in vitro of an in-frame GCG trinucleotide repeat in the human cellular glutathione peroxidase (GPX1) gene. In a population study of 110 alleles from 55 unrelated individuals, the allele frequencies for 4, 5, and 6 GCG repeats were 0.40, 0.35, and 0.25, respectively. No allele was associated with diminished enzyme activity. Current stocks of HL-60 cells, a human myeloid leukemia cell line, are homozygous for the 6-repeat allele. Early passage HL-60 cells frozen in 1976 show a 4/6 genotype and "intermediate" passage cells frozen in 1985 contain both 4/6 and 5/6 genotypes. Thus, the expansion of the repeat appears to have developed in the course of multiple passages of the rapidly proliferating cell line.
A 23-month-old female evaluated for profound anemia proved to have megakaryoblastic leukemia. The diagnosis is based on examination of bone marrow morphology, cytochemical characteristics, and immunophenotype. The chromosome complement of unstimulated blast cells in peripheral blood and bone marrow was 48,XX,+21,+21. Tetrasomy 21 is the sole clonal cytogenetic abnormality in this patient with megakaryoblastic leukemia. The constitutional complement of the patient is normal female, 46,XX.
The authors studied a patient with the simultaneous occurrence of chronic lymphocytic leukemia (CLL) and chronic myelogenous leukemia (CML). The coexistence of these two hematologic malignancies leads to questions about their cell of origin. Through analysis of this patient's DNA, the authors studied the derivation of the two malignancies. They separated the blood into a myeloid-rich fraction and a fraction containing the malignant lymphocytes. JH and bcr probes were used to study these loci in the myeloid and lymphoid fractions and in unfractionated white blood cells. The authors found that the unfractionated leukocytes contained the bcr and JH rearrangements. Conversely, the lymphoid fraction contained only the JH rearrangement, and the myeloid fraction contained only the bcr rearrangement, suggesting that these malignancies arose from separate stem cells. This is the first reported patient with simultaneously occurring CML and CLL definitively shown to arise from distinct progenitors, and this report raises questions about the origin of these two cell lines.
Recent studies have suggested a causal and pathogenetic relationship between holoprosencephaly and anencephaly. In support of the proposed relationship we report a sibship that includes anencephalic male twins and a female infant with a severe form of alobar holoprosencephaly, radial aplasia, and oligodactyly. The upper limb and brain malformations are considered to represent aprosencephaly syndrome. The coexistence of anencephaly and aprosencephaly within a sibship suggests that XK aprosencephaly syndrome may be an autosomal recessive disorder.
Human malignant mesothelioma of the pleura was successfully transplanted s.c. into athymic nude mice and grew as a solid neoplastic mass. Tumor growth resulted in death of the animals between 98 and 161 days after implantation. Minced samples of the growing tumor were propagated as a malignant peritoneal effusion. Animals with malignant ascites died predictably at 32 to 33 days. Light and electron microscopy, and immunocytochemistry demonstrated a similarity of the transplanted solid and fluid malignancies with the human primary mesothelioma. Cytogenetic analysis demonstrated a predominance of cells with a triploid number of identifiable but abnormal human chromosomes. This model, which mimics the clinical behavior of malignant mesothelioma in the human, may be of value in animal trials of chemotherapy and immunotherapy.
A previously healthy 2.5-year-old boy developed symptoms of acute pyelonephritis following an acute gastroenteritis. The patient received parenteral ampicillin and gentamicin for 72 hours and then ampicillin for an additional 11 days when the original urine and stool cultures grew Salmonella enteritidis, sensitive to ampicillin. The patient responded very well to treatment, but B-mode renal ultrasonogram revealed a left hydronephrosis and megaureter suggestive of longstanding obstruction of the ureterovesicular junction, later confirmed by other diagnostic studies and by surgical exploration and repair. Salmonella infection has been rarely documented to cause pyelonephritis in children. Obstructive uropathy appears to be a predisposing factor for this unusual complication of Salmonella enteritis.
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We describe further a patient previously reported to have "proteolytic and lipolytic deficiency of the exocrine pancreas." Features not previously reported include absent permanent teeth, hypoplastic alae nasi, scalp defect, normal thyroid function, and normal gonadotropins. Moreover, the normal amylase activity initially assumed to be of pancreatic origin proves to be of salivary origin. Thus the pancreatic deficiency is not only proteolytic and lipolytic but amylolytic as well. This disorder is identical with the "syndrome of congenital aplasia of the alae nasi, deafness, hypothyroidism, dwarfism, absent permanent teeth and malabsorption" subsequently reported by Johanson and Blizzard. The euthyroid status of this patient and that of another described in the literature suggest that hypothyroidism is probably not a major feature of this disorder. Our studies point to deficiency of the exocrine pancreas as the major cause of growth failure.
A Robertsonian balanced translocation of two D chromosomes was found in the bone marrow cytogenetic studies of a 70-year-old myeloproliferative disorder (MPD) woman. G-banding studies showed the translocation involved a 13q14q. An identical balanced t(13q14q) chromosomal pattern was found in her peripheral blood 3 years before the diagnosis of MPD as part of an investigation involving her daughter's reproductive difficulties. Her daughter is also a t(13q14q) balanced translocation carrier. The finding of a t(13q14q) in MPD may be coincidental or it may be predisposing to the development of MPD. Additional studies may elucidate this controversy.
A 9-year-old girl had no lacrimal puncta, tearing (alacrima), or salivation (aptyalism). The lack of salivation caused florid dental caries. The same condition was found in the proband's father and paternal grandfather. Inheritance of this previously unreported trait appears to be autosomal dominant with variable expressivity.
The syndrome of blepharophimosis, ptosis, and epicanthus inversus is a rare but well-documented autosomal dominant disorder. Although autosomal dominant inheritance has been repeatedly confirmed, several observers have noted that transmission of the trait is predominantly through an affected male parent. To our knowledge, no published observations have accounted for this unusual differential transmission. Described here is a family with typical features of this disorder and in addition primary amenorrhea in the affected women. The primary amenorrhea, which has not been previously documented in this disorder, does account for differential transmission in this family and possibly in other families. Since affected individuals are treated by ophthalmologists, the possible occurrence of this extraocular manifestation should be recognized in the management of patients and their families.
To our knowledge, there have been three prior reports of patients found, with trypsin-Giemsa banding, to be monosomic for the terminal q segment of chromosome 4. Described herein is a fourth patient with this chromosome abnormality. Comparison of these four patients suggests a characteristic phenotype in the 4q- syndrome: cleft palate, satyr deformity of the pinnae, snub nose, retrognathia and micrognathia, hypertelorism, oropharyngeal hypothonia or upper airway obstruction, cardiac defect, clinodactyly of the fifth fingers with absence of a flexion crease, simian lines, displaced or clinodactylous toes, and mental retardation. In the three prior reports, the 4q- syndrome resulted from a de novo deletion. In the present case, the 4q monosomy was inherited from the father, who had a 4;20 translocation.
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We report clinical observations and cytogenetic studies of an inherited form of partial trisomy 8q. Although complete trisomy 8 has in recent years proven to be a clinically recognizable syndrome, partial trisomy 8q has been documented in only six individuals. Of these, five were familial and also partially trisomic for chromosome 22. There has been only one prior report of partial trisomy 8q without partial trisomy 22. Review of these cases provides support for the recent suggestion that the phenotype of trisomy 8 may be caused principally by trisomy of the distal segment of 8q.