A case with 46, XX, del (11) (q21)

Ocular findings in Jacobsen syndrome

PURPOSE

To discuss the ophthalmic findings and their clinical significance in 10 new cases of Jacobsen syndrome (mental retardation, craniofacial anomalies, congenital heart defects, and blood dyscrasias) and to review the ophthalmic findings in all previously reported cases in the literature.

METHODS

Ten new cases of Jacobsen syndrome were collected and studied prospectively for detection of abnormal ophthalmologic examination findings. A total of 63 previously reported cases were identified from Medline and analyzed for ophthalmologic abnormalities.

RESULTS

The most common ophthalmologic findings in the new cases of Jacobsen syndrome included strabismus (90.0%), refractive error (90.0%), and ptosis (70.0%). Facial dysmorphism was also common and included hypertelorism, epicanthal folds, and down-slanting palpebral fissures. Uncommon ophthalmic findings included 5 patients with retinal vascular tortuosity, 1 with glaucoma, and 3 with amblyopia. In 63 cases reviewed, 36 reported ophthalmologic abnormalities. The most common findings included facial anomalies and ptosis. Only 5 of the 63 patients had evidence of strabismus, and none were reported to have retinal vascular tortuosity.

CONCLUSIONS

To prevent unnecessary vision loss in children with Jacobsen syndrome, proper screening for amblyogenic factors is imperative. We recommend a baseline complete ophthalmologic examination with subsequent follow-up examinations depending on the particular findings noted during the initial screening visit.

Partial deletion of the long arm of chromosome 11: ten Japanese children

The clinical features of partial deletion 11q were correlated with the size of the deleted region. Ten Japanese children with partial deletion of 11q were investigated. They were divided into three groups. Three patients in the first group had interstitial deletions and preserved subband q24.1. Six patients in the second group demonstrated terminal deletion of 11q including subband q24.1, with typical features of 11q- syndrome (Jacobsen syndrome). The third group included only one patient, who had terminal deletion of 11q without characteristics of typical 11q- syndrome. Prominent features of patients in the first group included severe mental and motor developmental delay, seizures, cleft lip and palate, and ophthalmological findings. Patients in the second group showed mild to moderate developmental delays without deterioration. Abnormalities in neuroimages, high intensity in the cerebral white matter in T2-weighted magnetic resonance (MR) images, and recurrent infections were not observed after the age of 7 years. The subject in the third group, with the smallest amount of deleted chromosome, did not show developmental delays, suggesting that some unknown genes related to developmental delays may be located adjacent to subband q24.1. Variation in the deleted parts of 11q resulted in different clinical features in each group.

Jacobsen syndrome: report of a patient with severe eye anomalies, growth hormone deficiency, and hypothyroidism associated with deletion 11 (q23q25) and review of 52 cases

We have evaluated a patient with Jacobsen syndrome. The patient presented with growth retardation, hypotonia, trigonocephaly, telecanthus, downward slanting palpebral fissures, bilateral inferior colobomas (of the iris, choroid, and retina), hydrocephalus, central nervous system (CNS) abnormalities, and an endocardial cushion defect, features commonly seen in Jacobsen syndrome. Endocrine evaluation showed growth hormone deficiency and central hypothyroidism. Chromosome analysis showed a 46,XX,del(11)(q23q25) de novo karyotype. Cytogenetically, the deletion appeared to include most of bands 11q23 and q24 and a portion of q25. Using chromosome specific paint probe, a combination of chromosome 11 centromere, telomere, and region specific cosmid probes from 11q14.1-14.3, 11q23.3, and 11q24.1, we have localised the deletion breakpoint to q24.1. Phenotype-karyotype correlation of patients with Jacobsen syndrome and specific deletions of chromosome 11q has enabled us to suggest that the critical region for this syndrome lies in close proximity to cytogenetic band 11q24. Although growth retardation is a consistent finding in 11q deletion syndrome, the presence of hypothalamic-pituitary hormone deficiency has not been reported previously.

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.

Partial deletion 11q: report of a case with a large terminal deletion 11q21-qter without loss of telomeric sequences, and review of the literature

We describe the cytogenetic findings and the dysmorphic features in a stillborn girl with a large de novo terminal deletion of the long arm of chromosome 11. The karyotype was 46,XX,del(11)(q21qter). By reviewing previous reports of deletion 11q, we found that cleft lip and palate are most frequently seen in proximal 11q deletions involving 11q21. Telomeric staining using the PRINS technique demonstrated normal telomeric sequences in the deleted chromosome 11.

Monosomy 11q: report of two familial cases and review of the literature

We present four children from two families with the typical 11q- phenotype resulting from an unbalanced segregation of a parental translocation. In the first family, the father had a 46,XY,t(5;11)(q24;q23.3) constitution. The father of the three other children had a 46,XY,t(11;17)(q23;p13) translocation. Despite associated partial deletion, three of the children had a typical 11q- phenotype. The fourth one, whose pregnancy was terminated in the second trimester, had a hypoplastic left heart but no other considered gross anomalies. A review of 36 previous cases, including 5 due to translocations (4 familial rearrangements, and 1 of unknown origin) is given with emphasis on the relationships between break-points and phenotype. Undescribed manifestations in our patients include agenesis of corpus callosum adactyly and malrotation of the gut.

Holoprosencephaly, ear abnormalities, congenital heart defect, and microphallus in a patient with 11q- mosaicism

We report on a newborn male with deletion of part of 11q, the 27th reported case. Our patient had some of the clinical characteristics of the 11q- syndrome, but his male gender, liveborn status, q21 breakpoint, and mosaicism were unusual. In addition, he demonstrated holoprosencephaly, with cyclopia and arhinencephaly, manifestations previously unreported in the 11q- syndrome. We discuss the above points and review the literature on 11q-.

Peters' anomaly associated with partial deletion of the long arm of chromosome 11

A 5-week-old boy with Peters' anomaly was found to have an interstitial deletion of the long arm of chromosome 11; no developmental delays or dysmorphic features were evident. His right cornea was enlarged and opaque with extensive pannus formation; the anterior chamber, iris, and lens were not visible. The left eye showed a central opacity and a superficial pannus; the optic disk and macula could not be visualized. He underwent bilateral corneal transplantation. Histologic examination of the corneal buttons confirmed the diagnosis. The potential genetic mechanisms in this case included a gene for this autosomal recessive disorder on the long arm of chromosome 11, generalized disruption of the embryogenesis of the anterior segment as a result of the deleted material, or simple autosomal recessive inheritance unrelated to the chromosomal deletion.

Towards an understanding of the molecular mechanisms regulating gene expression during diploidization in phylogenetically polyploid lower vertebrates

Polyploidization and regional gene duplication have occurred frequently during vertebrate evolution, providing the genetic material necessary for creating evolutionary novelties. Mammals, including man, can be regarded as diploid species with a polyploid history of evolution. Polyploidization steps during the phylogeny of mammals probably took place in the genomes of amphibian- or fish-like mammalian ancestors. The polyploid status has subsequently been shaped by the process of diploidization, leading to genomes that are polyploid with respect to the amount of genetic material and the number of gene copies, and diploid with respect to the level of gene expression and chromosomal characteristics. Phylogenetically tetraploid amphibian and teleost species together with their diploid close relatives can be used as a model system to study the effect of polyploidization and the mechanisms of diploidization of a parallel event during early mammalian evolution. Experimental evidence permits the assumption that the diploidization of gene expression in tetraploid cyprinid fish may be functionally correlated with structural modifications of the ribosomal components, RNA and protein. These findings are discussed in the light of reduced protein synthesis in diploidized tetraploid species and a mechanism to explain diploidization during mammalian evolution.

Brief clinical report: ring-11 chromosome: phenotype-karyotype correlation with deletions of 11q

The cytogenetic evaluation of a female infant with congenital anomalies led to the identification of the second reported case of a ring-11 chromosome. Unlike the previously described case, in which the patient had only minimal clinical findings and no demonstrable loss of material from the ring, our patient had numerous anomalies that were associated with a substantial deficiency of 11q material. The different phenotypes in these two cases represent variation in the amount and location of the chromosomal material lost during the genesis of the ring. The manifestations of this patient and the deletion of region q24 leads to qter from the ring-11 identify a specific chromosome deletion syndrome referred to as del (11q) syndrome.

Brief clinical report: deletion of the long arm of chromosome 11, [del(11)(q23)]

We report sporadic occurrence of deletion of the long arm of chromosome 11 (q23 leads to qter) in a male newborn infant with intrauterine growth retardation, craniofacial, cardiac, and orthopedic abnormalities and neonatal death but without genital abnormalities. This deletion is seen predominantly in females; here we emphasize the importance of an XX sex chromosome constitution as a factor determining phenotypic expression of and survival in the del(11q) syndrome. We also provide a description of the cardiovascular system from postmortem examination. The cardiac findings are similar to those of two previously autopsied cases and will assist in early clinical diagnosis of the 11q-syndrome.

Absence of constitutive heterochromatin in a partially identified supernumerary marker chromosome

A retarded child with multiple malformations was found to have a karyotype 47,XY,de1(11)(11 pter leads to q21:), +mar(11 qter leads to q21::?). The mitotically stable centric marker had no demonstrable C heterochromatin. Phenotype-karyotype correlation and the role of C heterchromatin in phenotypic effects are discussed.

Craniosynostosis and syndactyly: expanding the 11q-- chromosomal deletion phenotype

A patient with a partial deletion (q23 leads to qter) of the long arm of chromosome 11 presented with craniosynostosis and syndactyly. These characteristics, which have not been previously reported with 11q--, expand the phenotype of this syndrome and emphasise the need for chromosome analysis with banding techniques in multiple congenital anomaly syndromes, even if the patient could be classified as having a non-chromosomal syndrome.

Deletion of the long arm of chromosome 11: a clinical entity

A deletion of the long arm of chromosome No. 11, an aberration undetectable in conventional chromosome staining, was identified with Giemsa banding in a female infant with multiple congenital anomalies. A survey is given of the clinical findings in the few cases so far reported.

Chromosomal investigations in children with pyknolepsy on dipropylacetate monotherapy

We analyzed chromosome preparations obtained from leukocytes of ten children with pyknolepsy and treated with dipropylacetate (DPA) as monotherapy. Structural or numerical aberrations were not found more frequently in our patients than in five normal children (control group).

Partial deletion of long arm of chromosome 11: del (11) (q23)

The cytogenetic analysis of an infant with multiple congenital anomalies revealed a small deletion of the long arm of one No. 11 chromosome: 46,XX,del(11)(q23). The main clinical manifestations included: ocular colobomata, absent philtrum, severe congenital heart disease, contractures of the large joints and skin pigmentation. Both parents showed a normal chromosome constitution. In comparison to the previously reported cases of 11q-, the patient presented here had more severe congenital anomalies. The correlation of the size of the deletion, and the location of the break, with the physical findings is discussed.

Partial deletion of long arm of chromosome 11[del(11)(q23)]: Jacobsen syndrome. Two new cases and review of the clinical findings

Two cases, a boy and a girl, with the 11q-(Jacobsen) syndrome are reported. Findings common to both and typical for this chromosome aberration include a narrow protruding forehead, hypertelorism, non-horizontal position of the eyes, ptosis, strabismus, broad root, and short upturned tip of thenose, carp mouth, receding chin, misshapen ears, simian creases, and severe mental retardation. In addition, one patient had pyloric stenosis and an inguinal hernia. Growth retardation and microcephaly were not found in either of them. The karyotypes revealed de novo-deletions of the long arm of one chromosome 11,del(11)(q23).

The 11q-- syndrome: another case report

The clinical findings and developmental progress of a female infant with karyotype 46,XX,del(11)(q23) are described. Comparison is made with five other reported cases, and the suggestion of a new syndrome del 11q--is supported.

A girl with partial long-arm deletion of chromosome 11 and familial pericentric inversion of chromosome 9

A girl with 46, XX, del (11) (q23), inv (9) (p13, q13) is described. The patient shows many dysplastic signs mainly of the face and skull. The pericentric inversion of chromosome 9 has been inherited from the mother (46, XX, inv (9) (p13, q13)).

The 11q -- syndrome

An eighth case of terminal deletion of the long arm of chromosome eleven (11q--) is reported to emphasize both the distinctive facies, but otherwise non-specific nature of this disorder, and the female preponderance of affected patients. Growth and mental retardation, congenital heart disease and telecanthus are the other most constant features. The authors' experience with 3 unrelated cases in less than 2 years suggests that this syndrome is underdiagnosed.

The 18 p-syndrome. Report of four cases

Four children, two girls and two boys, were found to have a short arm deletion of chromosome No. 18. Three of them exhibit a typical dysmorphy of the face showing retraction of the midface, broad-based, flat nose, hypertelorism, epicanthus, "carp mouth", big, protruding, and low set ears, as well as a variable number of Turner-like features, failure of growth, mental retardation, and muscular hypotonia. A newly born child, who died at 2 days of age exhibited severe brain defects of holoprosencephalic series. The clinical and cytogenetic findings are compared with the reviewed data of the 18 p deletion. The hypothesis of "gene-dosis compensation" is discussed in order to explain the variable phenotypical expression of 18 p-syndrome as there is obviously to correlation between the extent of the deficiency and the expression of malformations.