Biomedical subjects
Publications and source records attributed to J J Hoo.
We observed three Chinese families in which congenital isolated funnel chest was segregating. This report confirms that funnel chest (pectus excavatum) can be transmitted as an autosomal dominant trait.
Two cases of familial paracentric inversion, one in the long arm of chromosome 2 and the other in the long arm of chromosome 8, are described. The first was ascertained in a woman who was studied because of recurrent abortions. The second was ascertained in the father of a girl with the trichorhinophalangeal syndrome and an interstitial deletion in 8q. The latter is the first case in which unequal crossing over in an inversion loop can be inferred in a male carrier of a paracentric inversion. The reasons for the relatively low frequency of paracentric inversions observed and factors which affect the pregnancy outcome are discussed.
The presence of supernumerary isochromosome 9p in duplicate in about 50% of bone marrow cells of an elderly female patient with myeloproliferative syndrome is reported.
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A case of de novo del(4)(q12q21.1) is presented. Three of four patients with comparable deletion show abnormal integumentary pigmentation, which is compatible with the known autosomal dominantly inherited piebald trait. Further analysis of breakpoints of five cases with proximal interstitial 4q deletion suggests the possible localization of the piebald trait gene within the band 4q12.
Abnormalities of chromosome 14 are encountered infrequently in clinical cytogenetics and only few studies of paracentric inversion have been published. This paper reports the first case of hypospadias associated with paracentric inversion of chromosome 14.
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The nature and the origin of a supernumerary marker chromosome in a mentally retarded boy were determined by various staining techniques on metaphase chromosomes and by GBG high resolution technique. The karyotype was found to be 47,XY, + inv dup(15) (pter----q13: :q13----pter) and the supernumerary chromosome was of maternal origin.
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The finding of an unbalanced t(18;22)pat chromosome rearrangement in a boy with multiple anomalies including apparent absence of the thymus is described. The observation is of interest because of the reported association of chromosome 22 rearrangements with the DiGeorge sequence. In contrast to previous reports of this association, the deletion involving chromosome 22 is confined to the short arm.
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An analysis of karyotype-phenotype correlations was carried out on a male infant with 46,XY, -9, +der(9)t(9;10)(p22;q25.2)mat. Cytogenetically, the patient had a 9p deletion and a concurrent 10q2 duplication. Clinically, he manifested predominantly the features of 9p deletion syndrome. An epistasis of 9p deletion over 10q2 duplication was evident in this patient. Possible explanations for this epistatic phenomenon are discussed.
Two sisters with similar clinical features are described. Their clinical manifestations include mental retardation, delayed speech development, low percentiles for height, weight and head circumference, dysmorphic ears, cubitus valgus, pseudoclubbing of fingers, flexion deformity of toes, small kidneys, elevated serum creatinine and blood urea nitrogen (BUN). High resolution chromosome analysis revealed a complete deletion of 16qh with a concurrent small deletion of the adjacent euchromatic segment 16q12.1 in one of the no. 16 chromosomes of both sisters, whereas the parents had normal no. 16 chromosomes. Length polymorphism of the 16qh regions appeared to indicate a maternal origin of the deleted no. 16 chromosome in both sisters. The clinical features of both sisters were attributed to the 16q12.1 deletion. Since both parents were cytogenetically normal, the two sisters were considered as a recurrence of a similar de novo interstitial deletion. Possible mechanisms which could lead to recurrence of a seemingly de novo event are discussed.
Rats were treated with amphetamine to induce an amphetamine psychosis which resembles paranoid schizophrenia. Brain catecholamines, brain beta-endorphin, serum prolactin as well as catechol-O-methyltransferase and monoamine oxidase were subsequently measured. The norepinephrine levels were significantly lower in brain regions of rats treated with amphetamine whereas levels of dopamine and beta-endorphin remained the same. No significant changes were found in the levels of catechol-O-methyltransferase, monoamine oxidase and serum prolactin. In view of recent findings by other investigators in this field, our results suggest an important role of the adrenergic system in the pathogenesis of amphetamine psychosis.
An 18-year-old intellectually normal male with characteristic features of the Langer-Giedion syndrome is reported. High resolution chromosome analysis showed a small deletion in the region of bands 8q24.11 and 8q24.12 in addition to an apparently balanced de novo translocation (2;9)(q21;q13). This finding provides additional information on the minimum deleted segment required to produce the Langer-Giedion syndrome and may indicate that deletions of this size or smaller are not necessarily associated with mental retardation.
A female infant with multiple congenital anomalies is presented. Cytogenetic study revealed the presence of a de novo, supernumerary, small telocentric chromosome exhibiting the banding pattern of the short arm of chromosome no. 10 [47,XX,+10p(pter----cen)]. Her clinical features were compatible with the 10p trisomy syndrome. Hexokinase (HK-1) activity was elevated in the patient's erythrocytes, which is consistent with an assignment of HK-1 to 10pter---cen10. The absence of a gene dosage effect for inorganic pyrophosphatase (PP) in this study indicates exclusion of PP from 10pter ----cen10, and therefore implies a regional assignment of cen10----10q24 for PP. Adenosine kinase (ADK) activity was within control limits, which is consistent with exclusion of ADK from 10pter----cen10.