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

A de novo subtelomeric monosomy 11q (11q24.2-qter) and trisomy 20q (20q13.3-qter) in a girl with findings compatible with Jacobsen syndrome: case report and review

We report on a 2-year-old dysmorphic girl with prenatal and postnatal growth deficiency, cardiopathy, left-sided hydronephrosis due to pyelourethral junction stenosis, frequent respiratory infections and psychomotor retardation, in whom a de novo unbalanced submicroscopic translocation (11q;20q) was detected by subtelomeric multiplex ligation-dependent probe amplification and fluorescence in situ hybridization analyses. Additional fluorescence in situ hybridization studies with locus-specific BAC probes and analyses with microsatellite markers revealed that this translocation resulted in a paternal chromosome 11q terminal deletion of approximately 8.9 Mb and a subtelomeric 20q duplication of approximately 3.7 Mb. A subtelomeric 20q trisomy has only been reported in four cases so far. A subtelomeric 11q deletion has been clinically reported in 18 patients. We review the clinical phenotype of these patients. We suggest that patients with a subterminal (11q24.2/25-qter) deletion may present with features of the well-known phenotype of terminal 11q deletion or Jacobsen syndrome.

Corpus callosum aplasia in a young patient with a parathyroid adenoma

A young man with primary hyperparathyroidism due to a parathyroid adenoma and aplasia of the corpus callosum is presented. We hypothesize a possible genetic association of the two pathologies: a proportion of the sporadic parathyroid adenomas are associated with genetic abnormalities of chromosome 11 and in some cases of corpus callosum aplasia, aneuploidy or polyploidy of this chromosome has been described.

Patient with trisomy 9p and a hypoplastic left heart with a tricentric chromosome 9

We present a patient with a hypoplastic left heart (HLH), dislocations of the hips and knees, and minor dysmorphic features, who had an abnormal karyotype that resulted in trisomy for 9p and a portion of 9q: 46,((, dic(or tri?)(9)(9pter --> 9q34::9q21 --> 9pter).ish(WCP9++).ish(D9Z5X4 +/+++). The derivative chromosome consisted of an additional copy of the proximal q arm and p arm attached to 9qter in an inverted fashion. Fluorescence in situ hybridization (FISH) using a chromosome 9 beta-satellite probe revealed three signals on the abnormal chromosome 9, suggesting the presence of 3 pericentromeric regions on the der(9). The 9q subtelomere was present on both the normal and derivative chromosome 9, suggesting that very little material, if any, is deleted.

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.

Craniofacial anomalies, deafness, brachydactyly, short stature, and moderate mental retardation due to a cryptic 6p;11q translocation

Monozygotic twin brothers are described who share clinical features which include: moderate mental retardation, short stature, macrocephaly, frontal bossing, ptosis, low-set ears, brachydactyly, 5th fingers clinodactyly, single palmar creases, cryptorchidism, and prelingual sensorineural deafness. One of the twins presented with mild cardiac dilatation and died at age 3(1/2) from cardiac arrest during an episode of acute respiratory infection. While chromosome analyses performed for both twins on peripheral blood showed apparently normal karyotypes, screening for all telomeric regions on the surviving propositus revealed a combination of partial 6p trisomy and partial 11q monosomy. A balanced reciprocal translocation was found in the father. The phenotype of the twins is most likely related to this cryptic chromosomal rearrangement. The fact that the phenotype in this family partially overlaps with some previously reported phenotypes is discussed.

Agenesis of corpus callosum: clinical description and etiology

In 135 children (aged 3 months to 15 years) with structural defects of the central nervous system found on magnetic resonance imaging, agenesis of the corpus callosum was evident in 7. The etiology of agenesis of the corpus callosum has been established in four children: partial trisomy of chromosome 13, partial duplication of the long arm of chromosome 10, Aicardi's syndrome, and intracranial bleeding during the fetal period as a result of injury. Agenesis of the corpus callosum coexisted with a Dandy-Walker malformation in one other patient, which suggests a genetic etiology. In spite of these variable etiologies, dysmorphic features were identified in all seven patients, as was psychomotor retardation. Epileptic seizures had occurred in six patients, and all manifested abnormalities on neurologic examination.

Ebstein anomaly associated with rearrangements of chromosomal region 11q

Ebstein anomaly (EA) is a relatively uncommon congenital heart defect and it is very rarely associated with a chromosomal anomaly. We report two distinct rearrangements of the chromosomal region 11q arm in two unrelated patients with Ebstein anomaly, renal malformation, minor anomalies, and the Pierre Robin sequence. The first patient had an interstitial deletion of chromosome 11 [46,XY,del(11)(11q21q23), and the other had a tertiary trisomy of chromosome 11qter (47,XX,+der(22)t(11;22)(q23;q11.2) Its association with either a chromosome 11q deletion or a duplication in some individuals suggests that a rearrangement of the 11q region is likely to cause a shift of the individuals' underlying liability to develop EA above a certain threshold.

Reciprocal translocation 4;11 with both adjacent-1 segregants viable within a family

We describe a family carrying a balanced 4;11 translocation in which both adjacent-1 segregants are viable. The proband had an unbalanced karyotype: 46,XY,der(11)t(4;11)(q34.3;q23.1)mat. At 8.5 years of age he showed trigonocephaly, hypertelorism, epicanthal folds, down-slanting palpebral fissures, low-set ears, anteverted nares, down-turned carp-shaped mouth, and bilateral fifth finger clinodactyly. His maternal aunt was also dysmorphic with high-arched palate, short philtrum and mild developmental delay. Her karyotype was 46,XX,der(4)t(4;11)(q34.3;q23.1)pat. Other relatives who likely carried a chromosomally unbalanced segregant were identified from photographs and medical records. We compare the clinical findings in our family with descriptions of other similar karyotypic abnormalities from previous case reports.

At least nine cases of trisomy 11q23-->qter in one generation as a result of familial t(11;13) translocation

Carriers of balanced reciprocal translocations may have a (high) risk for producing liveborn children with an unbalanced karyotype. We report a large family in which a translocation between the long arm of chromosome 11 and the short arm of chromosome 13 is segregating in at least five generations. During the course of our study 15 carriers of the balanced translocation were identified and nine cases of partial trisomy of the long arm of chromosome 11 were detected during pre- and postnatal studies. Several of the patients were thoroughly clinically examined and compared with similar published cases.

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.

Neuroblastoma in a boy with MCA/MR syndrome, deletion 11q, and duplication 12q

Deletion 11q23-->qter and duplication 12q23-->qter are described in a boy with neuroblastoma, multiple congenital anomalies, and mental retardation. The patient has clinical manifestations of 11q deletion and 12q duplication syndromes. The possible involvement of the segment 11q23-->24 in the cause of the neuroblastoma is discussed.

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.