Partial monosomy of chromosome 10 short arms

Barakat syndrome revisited

Barakat syndrome also known as HDR syndrome (Online Mendelian Inheritance in Man [OMIM] 146255), was first described by Barakat et al. in . It is a rare genetic disorder characterized by the triad of hypoparathyroidism "H," sensorineural deafness "D," and renal disease "R." The defect is caused by deletions in chromosome 10p14 or mutations in the GATA3 gene. Although the syndrome has been phenotypically defined by this triad the literature identifies cases with different components with, or without GATA3 defects making the definition of the syndrome confusing. We analyzed 180 cases and attempted to define the phenotype of the syndrome and suggest guidelines for diagnosis. We suggest that the diagnosis could be confirmed in patients who have all three components, and in those who have two components with a positive family history. GATA3 testing is optional to establish the diagnosis in these patients. The syndrome should be considered in patients with isolated "D" where other causes of "D" have been excluded and those with isolated "R," especially if there is family history of any of these components. In these instances, confirmatory GATA3 testing is indicated to confirm the diagnosis. In patients with nonsurgical "H," where "D" and "R" have been conclusively ruled out GATA3 studies are not needed as none of these patients were shown to be GATA3 haploinsufficient. Only 64.4% of patients in our review had "HDR." Some findings might have not been recognized or may could have appeared later in life, but it is evident that this syndrome is genotypically heterogeneous.

Interstitial deletion of 10p and atrial septal defect in DiGeorge 2 syndrome

We present molecular genetic investigations of a 4-year-old boy with craniofacial dysmorphism and developmental delay. Trivial mitral and tricuspid regurgitation without gross structural abnormality was diagnosed by echocardiography. High-resolution chromosome analysis revealed an interstitial deletion, del(10)(p12.1p12.32). To characterize the deletion size and breakpoints, we performed fluorescence in situ hybridization analysis using 27 BAC clones. Our data demonstrate an approximately 5.5 Mb deletion del(10)(p12.1p12.31). Surprisingly, the BAC clone RP11-56H7 that contains NEBL, an apparent downstream gene of the cardiogenic transcription factor HAND2 previously shown to be deleted in the patients with DiGeorge 2 syndrome and 10p13 deletion, was deleted in our patient with 10p12.1-p12.31 deletion. In addition, we provide clinical data and results of molecular analysis for a patient with multiple congenital anomalies including Ebstein's anomaly, kidney malformations, and 10p13-p14 deletion. We also reviewed 19 patients with congenital heart defects and deletions involving 10p and propose that atrial septal defect (ASD) is a common cardiac anomaly associated with DiGeorge 2 syndrome. Based on genotype-phenotype analysis of published patients and those reported herein, we propose an approximately 1.0 Mb critical region between loci D10S547 and D10S2176 in 10p14 to be associated with ASD. Considering that septal defects are the most frequent congenital heart anomaly, we suggest that further investigations in the 10p critical region are important to identify gene(s) responsible for this common birth defect.

MRI findings in a patient with partial monosomy 10p

Partial monosomy 10p is a rare chromosomal disorder characterised by frontal bossing, micrognathia, congenital heart defects, vesicoureteral abnormalities, and developmental delay. This is the first report to describe seizures not associated with hypocalcaemia, as well as cortical atrophy and decreased white matter volume on magnetic resonance imaging, in a patient with documented partial monosomy 10p. The neuroradiographic abnormalities found in this patient provide a first step towards understanding the aetiology of the developmental delay and ventriculomegaly associated with this chromosomal abnormality.

HDR syndrome (hypoparathyroidism, sensorineural deafness, renal dysplasia) associated with del(10)(p13)

A combination of hypoparathyroidism, sensorineural deafness, and renal dysplasia has been considered to be a new syndrome inherited in an autosomal dominant fashion; we name the condition "HDR syndrome." We describe a Japanese girl who has HDR syndrome associated with de novo del(10)(p13). The chromosome deletion suggests that the putative gene(s) responsible for HDR syndrome is located at a 10pter-->p13 region.

Velo-cardio-facial and partial DiGeorge phenotype in a child with interstitial deletion at 10p13--implications for cytogenetics and molecular biology

We report on a female with a interstitial deletion of 10p13 and a phenotype similar to that seen with the 22q deletion syndromes (DiGeorge/velo-cardio-facial). She had a posterior cleft palate, perimembranous ventricular septal defect, dyscoordinate swallowing, T-cell subset abnormalities, small ears, maxillary and mandibular hypoplasia, broad nasal bridge, deficient alae nasi, contractures of fingers and developmental delay. This could indicate homology of some developmental genes at 22q and 10p so that patients with the velocardiofacial phenotype who do not prove to be deleted on 22q are candidates for a 10p deletion.

Interstitial deletion of the short arm of chromosome 10: report of a case and review of the literature

The fifth patient with an interstitial deletion of the short arm of chromosome 10 is described. She showed most of the features observed in other known patients at age 20, including psychomotor retardation, distinct facial dysmorphism, abnormally shaped skull and cardiac malformation, while she did not show any growth retardation. The elevation of serum IgG level was observed from age 15, but she did not show DiGeorge syndrome. These differences would be explained by the differences in the amount of deleted segments using high resolution chromosome banding and molecular methods.

Family with partial monosomy 10p and trisomy 10p

We report on a family with an abnormality of 10p. The propositus has monosomy for the distal region of 10p and severe psychomotor delay, growth failure, congenital heart defect, multicystic kidney, grade V vesicoureteric reflux, and neurosensory hearing loss. The mother and the elder brother of the propositus carry a balanced reciprocal translocation (5q;10p)(q35.3;p12.3). A retarded and epileptic maternal aunt was found to have dup(10p). Study of the family history led to the successful obstetric management of a subsequent twin pregnancy in which an affected fetus with dup(10p) was identified and selectively terminated, while the other normal twin was delivered at term without problems.

Deletion of the short arm of chromosome 10 (10p13): report of a patient and review

Since the first description by Elliot et al. [1970, Am J Dis Child 119:72-73] of a probable partial deletion of chromosome 10p, 17 other cases have been reported. The phenotypic expression is variable, but the craniofacial malformations constitute a more consistent finding. The 10p deletion syndrome has been associated with the DiGeorge anomaly in several patients. We report on an additional case of 10p deletion syndrome and review the literature.

Simultaneous partial monosomy 10p and trisomy 5q in a case of hypoparathyroidism

We report a case of monosomy for the distal region of the short arm of chromosome 10 (p13----ter) associated with trisomy for the terminal region of the long arm of chromosome 5 (q35.2----ter) that had originated from adjacent 1 segregation of a maternal reciprocal balanced translocation (5;10)(q35.2;p13). We review the clinical findings of previously reported cases of both partial monosomy for 10p and of partial trisomy for 5q, but to our knowledge there are no previous reports of the effects of these two chromosome anomalies together. Clinically our patient showed features typical of partial monosomy for 10p (including hypothyroidism) rather than partial trisomy 5q.

Apparent cleidocranial dysplasia associated with abnormalities of 8q22 in three individuals

Cleidocranial dysplasia is an autosomal dominant, generalised skeletal disorder characterised by variable clavicular hypoplasia, frontal bossing, multiple Wormian bones, and delayed eruption of the teeth. The gene locus for this syndrome has not yet been assigned. Three individuals with manifestations of cleidocranial dysplasia associated with rearrangements of chromosome 8q22 are described. The evidence presented suggests that the gene for cleidocranial dysplasia may be located on chromosome 8q in humans in a region showing homology to mouse chromosome 3.

A new syndrome of congenital hypoparathyroidism, severe growth failure, and dysmorphic features

Twelve infants (six boys, six girls) with severe hypocalcaemic tetany or convulsions were seen over a three year period. Nine patients were symptomatic in the newborn period. Their hypocalcaemia was associated with hyperphosphataemia and very low concentrations of immunoreactive parathyroid hormone. None of the babies suffered from congenital cardiac disease. Cell mediated immunity, measured in five patients, was normal. There were no chromosomal abnormalities but all patients shared several dysmorphic features including deep set eyes, microcephaly, thin lips, beaked nose tip, external ear anomalies, micrognathia, and depressed nasal bridge. Mental retardation of varying degree was found in all patients. All had severe intrauterine and postnatal growth retardation. Four patients have died. The remaining eight patients are on treatments with vitamin D and calcium supplements with no change in their growth pattern. We believe that this association of congenital hypoparathyroidism with severe growth failure and dysmorphism represents a new syndrome.

Cytogenetic findings in a prospective series of patients with DiGeorge anomaly

High-resolution cytogenetics analysis of peripheral blood lymphocytes was done prospectively on 27 of 28 patients with features of DiGeorge anomaly. Twenty-two patients (81%) had normal chromosome studies with no detectable deletion in chromosome 22. Five patients (18%) had demonstrable chromosome abnormalities. Three patients had monosomy 22q11, one due to a 4q;22q translocation, one due to a 20q;22q translocation, and one due to an interstitial deletion of 22q11. One patient had monosomy 10p13, and one patient had monosomy 18q21.33, although the latter had subsequent resolution of T-cell defects. These findings are consistent with the heterogeneity of DiGeorge anomaly but confirm the association with monosomy 22q11 in some cases. However, monosomy 10p13 may also lead to this phenotype. Because of these associated chromosome findings, cytogenetic analyses should be done on patients with suspected DiGeorge anomaly. This is particularly important since many of the abnormalities involving chromosome 22 are translocations that can be familial with a higher recurrence risk. Since only one subtle, interstitial deletion of chromosome 22 was observed, it is not clear whether high-resolution cytogenetic analysis is cost beneficial for all such patients.