Brain size evolution in pipefishes and seahorses: the role of feeding ecology, life history and sexual selection.

Brain size varies greatly at all taxonomic levels. Feeding ecology, life history and sexual selection have been proposed as key components in generating contemporary diversity in brain size across vertebrates. Analyses of brain size evolution have, however, been limited to lineages where males predominantly compete for mating and females choose mates. Here, we present the first original data set of brain sizes in pipefishes and seahorses (Syngnathidae) a group in which intense female mating competition occurs in many species. After controlling for the effect of shared ancestry and overall body size, brain size was positively correlated with relative snout length. Moreover, we found that females, on average, had 4.3% heavier brains than males and that polyandrous species demonstrated more pronounced (11.7%) female-biased brain size dimorphism. Our results suggest that adaptations for feeding on mobile prey items and sexual selection in females are important factors in brain size evolution of pipefishes and seahorses. Most importantly, our study supports the idea that sexual selection plays a major role in brain size evolution, regardless of on which sex sexual selection acts stronger.

SLUG (SNAI2) overexpression in embryonic development.

The Snail-related zinc-finger transcription factor, SLUG (SNAI2), is critical for the normal development of neural crest-derived cells and loss-of-function SLUG mutations have been proven to cause piebaldism and Waardenburg syndrome type 2 in a dose-dependent fashion. However, little is known about the consequences of SLUG overexpression in embryonic development. We report SLUG duplication in a child with a unique de novo 8q11.2-->q13.3 duplication associated with tetralogy of Fallot, submucous cleft palate, renal anomalies, hypotonia and developmental delay. To investigate the effects of Slug overexpression on development, we analyzed mice carrying a Slug transgene. These mice were morphologically normal at birth, inferring that Slug overexpression is not sufficient to cause overt morphogenetic defects. In the adult mice, there was a 20% incidence of sudden death, cardiomegaly and cardiac failure associated with incipient mesenchymal tumorigenesis. These findings, while not directly implicating Slug in congenital and acquired heart disease, raise the possibility that Slug overexpression may contribute to specific cardiac phenotypes and cancer development.

A case of mistaken identity. A rare presentation of gonadal dysgenesis.

BACKGROUND: The incidence of gonadal dysgenesis (hermaphroditism) is recognised to be low. Rarer still is an initial late presentation in the general practice setting. OBJECTIVE: To present a case study of a 35 year old man diagnosed as a hermaphrodite after routine investigations in general practice for lower abdominal pain. He has normal male external genitalia, a fully formed uterus and vagina, with no identifiable gonads. DISCUSSION: This incidental finding in general practice is supported by a 46,X,i(Yp)/45,X karyotype and mosaicism for an isochromosome of the short arm of the Y. It is not unusual that with normal male genitalia, such patients are likely to survive undiagnosed or incorrectly diagnosed into adulthood.

Rapid detection of euchromatin by Alu-PRINS: use in clinical cytogenetics.

Alu-PRINS was successful in providing positive identification of euchromatin when oligoprimers were used at either extremity of the consensus Alu sequence. This technique was sensitive, as shown by the ability to detect small regions of euchromatin translocated to the short arm of an acrocentric chromosome. Since the Alu-PRINS technique is rapid and relatively simple, it will be useful in the diagnostic cytogenetics laboratory for the assessment of aberrant short arms of acrocentric satellites. This technique was also useful in defining the structure of small accessory marker chromosomes.

Chromosome 3p23 break with ring formation and translocation of displaced 3p23-->pter segment to 6pter.

An 11 year old boy with short stature, learning difficulties, and no obvious facial anomalies has a ring (3)(p23q29) formed by a break in the short arm at 3p23 and subsequent fusion with 3qter. A second rearrangement involving translocation of the displaced 3p23-->pter segment to chromosome 6 at 6pter is non-reciprocal with no obvious loss of distal 6pter material. The involvement of one chromosome in two separate rearrangements is uncommon. The patient's relatively mild phenotype appears to be associated with the "ring syndrome" and ring instability in division rather than from any segmental aneuploidy resulting from the presence of the two rearrangements.

Familial Klippel-Feil syndrome and paracentric inversion inv(8)(q22.2q23.3).

Klippel-Feil Syndrome (KFS) is characterized by congenital vertebral fusion believed to result from faulty segmentation along the embryo's developing axis. KFS appears to be a heterogeneous disease often associated with craniofacial malformation. Here we provide the first evidence of a familial KFS gene locus on 8q, where an inv(8)(q22.2q23.3) has been found segregating with congenital vertebral fusion. The four-generation KF2-01 family present with dominant form of the KFS where the sequence of vertebral fusion was confined to the cervical spine (always including the C2-3 fusion and reduced expression of the C4-5 and C6-7 fusions) in association with malformation of laryngeal cartilages and mild-to-severe vocal impairment.

Reassignment of human renin gene to chromosome 1q32 in studies of a (1;4)(q42;p16) translocation.

The human renin gene (REN) has been assigned to chromosome 1q42. Linkage studies are, however, inconsistent with this localization. We therefore reexamined the question of the location of REN using a patient whose distal chromosome 1q arm was translocated to chromosome 4 [(1;4)(q42;p16)]. In situ hybridization using a 3H-labelled REN probe demonstrated hybridization signals confined to the q32 band of chromosome 1, with radioactivity in the translocated 1q42 region being similar to the low levels along all other chromosomes.

Molecular cytogenetic and clinical studies of 42 patients with marker chromosomes.

The molecular cytogenetic characterization and clinical details of 20 patients with marker chromosomes are presented. These 20 patients, together with another 22 patients previously published, represent a cohort in which the chromosomal origin of the marker chromosomes was successfully determined in all but one case. Examination of the pooled data suggests that the satellited markers derived from chromosomes 14, 15 (when metacentric or submetacentric), those whose origin is either 13 or 21, and those small ring autosomal markers derived from both alphoid and satellite II or III pericentric heterochromatin of chromosomes 1, 9, 15, and 16 are all associated with a low risk of phenotypic abnormality. The markers identified as i(18p), ring chromosomes derived from various autosomes, and satellited markers derived from chromosome 22 are associated with a high risk of phenotypic abnormality. The phenotype of patients with acrocentric markers derived from chromosome 15 was equivocal, perhaps as a result of imprinting. Additional data are required to confirm these trends. The mild mental retardation and abnormal face of a patient with a small ring chromosome derived from chromosome 4 are described. Identification of patients with small rings originating from particular chromosomes may allow the recognition of new syndromes.

Multiple exostoses in a patient with t(8;11)(q24.11;p15.5).

The occurrence of multiple exostoses in a carrier of a balanced translocation t(8;11) (q24.11;p15.5) is described. The breakpoint on chromosome 8 is at proximal q24.1 within the critical region reported for Langer-Giedion syndrome.

Acute myelomonocytic leukemia with bone marrow eosinophilia and inv(16)(p13q22),t(1;16)(q32;q22).

A two-year-old girl presenting with de novo acute myelomonocytic leukemia with eosinophilia (French-American-British [FAB] classification, M4Eo) and inv(16)(p13q22), t(1;16)(q32;q22) involving the same chromosome 16 is described. This is the second report of a variant translocation of an inverted chromosome 16 with chromosome 1 at 1q32. However, the segment 1q32----1qter has been exchanged for 16q22----qter and not 16p13----pter, as reported in the previous case. The additional break at 1q32 and the juxtaposition of 1q32----qter onto chromosome 16 could be relevant to the pathogenesis of the disease.

First and second complete remissions in a HIV positive patient following remission induction therapy for acute non-lymphoblastic leukaemia.

A small number of patients positive for the human immunodeficiency virus (HIV) have been reported as developing acute non-lymphoblastic leukaemia (ANLL) and none has achieved remission despite attempts at treatment. We report on a 34-year-old HIV positive heterosexual intravenous drug user who presented with ANLL (FAB classification M5, Monoblastic) and entered remission following one cycle of cytosine arabinoside and daunorubicin according to the 7-3 protocol of the Australian Leukaemia Study Group (ALSG). This was followed by consolidation of 5-2 as per ALSG and one cycle of maintenance with low dose cytosine arabinoside. Ten months after remission, he relapsed but achieved a second remission with the ALSG 7-3-7 protocol (7-3 plus etoposide) followed by consolidation with 5-2-5. He remained HIV positive but showed little progression towards the acquired immunodeficiency syndrome despite the intense immunosuppression. The duration of his second remission was five months. The patient died of septicaemia during the third attempt at remission induction 18 months after diagnosis. We conclude that HIV seropositivity is not an absolute contraindication to aggressive chemotherapy in those patients who develop ANLL.

Localization of human glandular kallikrein-1 gene to chromosome 19q13.3-13.4 by in situ hybridization.

Humans possess 3 fully characterized kallikrein-like genes. The gene expressed in kidney, pancreas and salivary gland (KLK), and the gene encoding prostate-specific antigen (APS) have been localized to chromosome 19q13.2-qter. The present study describes the localization of the remaining gene, hGK-1, which has highest homology to and a similar tissue specificity of expression as the APS gene. Using a [3H]-labeled probe derived from a hGK-1 genomic clone, we demonstrated hybridization confined to the q13.3 and q13.4 bands of chromosome 19 and suggest that kallikrein genes may possibly be located near the border of these two bands.

Ring chromosomes in hypodiploid and hypotetraploid clones from an elderly patient with plasma cell leukemia.

We describe a 77-year-old woman who had with what appears to be the first case of plasma cell leukemia (PCL) with a ring chromosome of variable size. Of the three clones evident, two of them were abnormal: a 41,X,-X hypodiploid clone with rings of two different sizes, and a 81-82,XX hypotetraploid clone with a double-sized dicentric ring or variable double rings. Additional structural and numerical abnormalities included a 14q+ marker, deletions of two chromosomes 1 and monosomies 8 and 13, all previously reported in PCLs. Ring chromosomes have been associated with a poor prognosis, especially in elderly patients. The patient declined active treatment and died within 4 weeks of diagnosis.

Trisomy 4 in a case of acute biphenotypic leukemia.

Trisomy 4 was the sole chromosome anomaly in a 5-year-old girl with acute leukemia. Morphologically, there appeared to be distinct myeloid and lymphoid blast cells on presentation. Immunophenotyping, however, showed extensive overlap of myeloid and lymphoid markers, confirming the leukemia to be biphenotypic rather than true "bilineal." She attained remission only after lymphoid-cell-specific induction was added to the initial "myeloid type" induction. She relapsed 4 years later with morphologically acute lymphocytic leukemia (French-American-British L2 type) despite still retaining the original immunophenotypic characteristics. She was successfully reinduced and subsequently received an autologous bone marrow transplant. Second relapse, morphologically and immunophenotypically similar to the first, occurred 5 months after transplant.

Multiple abnormalities in a child with partial duplications of 10p and 13q from a 3:1 segregation of a maternal t(10;13) translocation.

Partial duplications of 10p and 13q in association with partial deletions of other chromosome segments have been variously reported. We describe here a female child with multiple congenital abnormalities and combined partial duplications of 10p and 13q resulting from a 3:1 segregation of a maternal t(10;13)(p13;q22). In comparing the phenotypic features of the two chromosome imbalances, the expression of features typical of partial duplication 10p appeared more pronounced.

Localization of human cardiac beta-myosin heavy chain gene (MYH7) to chromosome 14q12 by in situ hybridization.

The genes coding for each human cardiac myosin heavy chain (alpha-MHC and beta-MHC, MYH6 and MYH7, respectively) are tightly linked and the alpha-MHC gene has been assigned to chromosome 14. In order to provide a more precise regional localization, in situ hybridization experiments were carried out using a 3H-labeled probe derived from a beta-MHC genomic clone. The results demonstrated that the human cardiac MHC genes are located within the q12 band of chromosome 14.

Duplication of 5q11.2----q13.1 from a familial (5;20) balanced insertion.

A 2-year-old boy with gross motor delay and few minor anomalies has a pure duplication of a small segment of chromosome 5q11.2----q13.1. A balanced insertion of this 5q segment into chromosome 20q proximal to the centromere has been found in his father, uncle, and paternal grandmother.

A new syndrome with mental retardation, short stature and an Xq duplication.

We describe a new X-linked syndrome of marked short stature, severe intellectual handicap and an unusual facial appearance. High resolution prometaphase banding showed affected males to have an X chromosome tandem duplication; their karyotypes were designated 46,dup(X) (q13.1-q21.1)Y. In carrier females the abnormal X chromosome was late replicating. To verify the duplication, gene dosage studies were performed using an enzyme assay and DNA techniques. Prenatal diagnosis is available for carrier females using chromosome analysis of amniocytes or chorionic villi.

Deletion 15q21.1----q22.1 resulting from a paternal insertion into chromosome 5.

A 15 month old boy with an interstitial deletion 15q derived from a paternal insertion (5;15)(q31.3;q21.1q22.1) is described and compared with one other reported case. A beak like nose with hypoplastic nasal alae, a thin upper lip, failure to thrive in infancy with later onset of obesity, and severe mental retardation are features common to both.