A novel interstitial deletion of 2q22.3 q23.3 in a patient with dysmorphic features, epilepsy, aganglionosis, pure red cell aplasia, and skeletal malformations.

Many chromosomal deletions encompassing the 2q23.1 region have been described ranging from small deletions of 38 kb up to >19 Mb. Most phenotypic features of the 2q23.1 deletion syndrome are due to a MBD5 gene loss independent of the size of the deletion. Here, we describe a male patient harboring a novel interstitial deletion encompassing the 2q22.3 q23.3 chromosomal region. Array-CGH revealed a 7.1 Mb deletion causing haploinsufficiency of several genes including MBD5, ACVR2, KIF5C, and EPC2. This patient presents with additional findings to those already described in individuals who have deletions of MBD5 including toes absence of halluces, pure red cell aplasia, and intestinal aganglionosis. Interestingly, in the deleted region there are previously identified regulatory sequences which are located upstream to ZEB2, which is associated with Hirschsprung disease (HSCR). Several genes have been associated with pure red cell aplasia, but to our knowledge, this is the first time that 2q deletion is associated with this phenotype. These additional findings should be added to the list of manifestations associated with 2q deletion, and provide support for the hypothesis that this individual has a true contiguous gene deletion syndrome.

Unbalanced translocations involving chromosome region 10q25.3q26.3 in patients with intellectual disability and complex phenotypes.

We describe 2 Ukrainian families with unbalanced reciprocal translocations (RTs) involving the distal part of chromosome 10q. In both families, the fathers were healthy carriers of the RT. Two affected patients from the first family had an ∼2.3-Mb loss at 10q26.3 and an ∼25-Mb gain at 2q35qter, and the patient from the other family had an ∼12.5-Mb loss at 5p15.2pter and an ∼18-Mb gain at 10q25.3q26.3. We assume that intellectual disability (ID) in association with congenital anomalies observed in our patients was the result of the cumulative effect of both gains and losses of the chromosomal regions involved in each translocation. Comparison of the sizes of the deleted and duplicated segments in our families as well as in other published families with translocations affecting the distal part of 10q showed that generally deletions seem to be ∼2 times more harmful than duplications of the same size. The data obtained here may contribute to improve the diagnosis and genetic counseling of families with similar chromosomal imbalances.

[Probability rate of unbalanced offspring at birth and risk of unfavorable pregnancy outcomes in families of carriers of chromosomal reciprocal translocations involving chromosome 7]. / Ocena prawdopodobienstwa urodzenia dziecka z niezrównowafonym kariotypem oraz ryzyka wystqpienia róznych patologii ciazy w rodzinach nosicieli translokacji chromosomowych wzajemnych angazujacych chromosom 7.

INTRODUCTION: Carriership of reciprocal chromosomal translocation (RCT) may be the reason the occurrence of congenital malformations in the offspring, early neonatal death, stillbirth, and recurrent miscarriages due to unbalanced karyotype of gametes. The probability rate for individual categories of unfavorable outcomes depends on the kind of chromosome involved and is individually variable. OBJECTIVES: The aim of study was to estimate the probability rates for unbalanced offspring and to evaluate the risk for different categories of unfavorable pregnancy outcomes, depending on the size of chromosomal segment with differentiation between maternal/paternal origin of the reciprocal chromosomal translocations involving chromosome 7p (RCT-7p) and 7q (RCT-7q). In addition, the use of the obtained results has been illustrated by the example of a family with unique RCT t(7;9)(p21.3,p23). MATERIAL AND METHODS: Empirical and cytogenetic data on 341 pregnancies and offspring of 133 carriers were collected from 69 pedigrees of carriers of RCT-7p and RCT-7q at risk for a single 7 segment imbalance. The probability rates of particular form of pregnancy pathology have been calculated according to the method of Stengel-Rutkowski and Stene, including all forms of meiotic segregation and their survival rates after fertilization to term childbirth. RESULTS: The probability rates for unbalanced offspring for carriers of RCT-7p after 2:2 disjunction and adjacent-1 segregation were calculated as 5.5% +/- 2.2% (6/108); for maternal (MAT) and paternal (PAT) carriers were about < 1% (0/56) and 13.6 +/- 5.2% (6/44) (p = 0.04) respectively. Considering different segment lengths of 7p, the following values for shorter and longer segments were obtained: 23.0 +/- 11.7% (3/13) for 7p21-->pter; 3.3 +/- 3.3% (1/30) for 7p 14-->pter and 3.1 +/- 2.1% (2/65) for 7p 1-->pter The risk figures for stillbirth/earl neonatal death were estimated at 2.8 +/- 1.6% (3/108), but for miscarriage were calculated at 25.9 +/- 4.2% (28/108) for carriers RCT-7p. The probability rates for unbalanced offspring at birth for carriers of RCT-7q were calculated as 2.7 +/- 1.5% (3/111); for MAT and PAT carriers were 3.5 +/- 2.0% (3/86) and < 2.6% (0/19) respectively. Considering different segment lengths of 7q, the following values for shorter and longer segments were obtained: 6.2 +/- 6.1% (1/16) for 7q33-->qter; 5.3 +/- 3.6% (2/38) for 7q32-->qter and < 0.82% (0/57) for 7q11-->qter. The risk figures for stillbirth/early neonatal death were estimated at 9.9 +/- 2.8% (11/111), but for miscarriage were calculated at 34.2 +/-4.5% (38/111) for carriers RCT-7q. The probability estimated values for unbalanced fetuses, evaluated prenatally in the second trimester of pregnancy for carriers of RCT-7p and RCT-7q were similar i.e. 41.7 +/- 14.2% (5/12) and 46.7 +/-12.9% (7/15), respectively. CONCLUSIONS: 1. The probability rates for unbalanced offspring and the risk values for individual categories of unfavorable outcomes for carriers of RCT-7 are different and depend on the size of chromosome 7 segment involved in RCT 2. The probability rate for unbalanced offspring for paternal carriers of RCT-7p is higher than for maternal carriers (p = 0.04). 3. It is suggested that the probability rate for unbalanced offspring for maternal carriers of RCT-7q may be higher than for paternal carriers.

4q32-q35 and 6q16-q22 are valuable candidate regions for split hand/foot malformation.

On the basis of the Human Cytogenetic Database, a computerized catalog of the clinical phenotypes associated with cytogenetically detectable human chromosome aberrations, we collected from the literature 102 cases with chromosomal aberrations and split hand/foot malformation or absent fingers/toes. Statistical analysis revealed a highly significant association (P<0.001) between the malformation and the chromosomal bands 4q32-q35, 5q15, 6q16-q22 and 7q11.2-q22 (SHFM1). Considering these findings, we suggest additional SHFM loci on chromosome 4q, 6q and probably 5q. The regions 4q and 6q have already been discussed in the literature as additional SHFM loci. We now show further evidence. In the proposed regions, there are interesting candidate genes such as, on 4q: HAND2, FGF2, LEF1 and BMPR1B; on 5q: MSX2, FLT4, PTX1 and PDLIM7; and on 6q: SNX3, GJA1, HEY2 and Tbx18.

[Probability rates for different pregnancy outcomes in carriers of reciprocal chromosomal translocations involving chromosome 13]. / Prawdopodobienstwo wystapienia róznych patologii ciazy w rodzinach nosicieli translokacji chromosomowych wzajemnych angazujacych chromosom 13.

OBJECTIVES: The aim of study was to estimate the probability rates for unfavorable pregnancy outcomes in carriers of reciprocal chromosomal translocations involving 13 chromosome (RCT-13q). MATERIAL AND METHODS: We collected total empirical data about 232 pregnancies of 56 carriers coming from 28 pedigrees. RCT classification was based on classic cytogenetic methods for interpretation of breakpoint position. The probability rates of particular type of pathology related to the total number of pregnancies after ascertainment correction have been calculated with the help of Stengel-Rutkowski and Stene method. RESULTS: The risk figures for unbalanced offspring after 2:2 disjunction and adjacent-1 segregation for the whole group of pedigrees were calculated as 5.2 +/- 1.7% (9/173)--medium risk, for maternal (MAT) and paternal (PAT) carriers were about 6.2 +/- 2.3% (7/173) and 4.8 +/- 3.3% (2/42) respectively. Considering different segment lengths of 13q, similar values for shorter and longer segments were obtained [4.3 +/- 1.9% (5/115) for 13q21-->qter and 7.0 +/- 3.3% (4/58) for 13q12-->qter]. The risk figures for miscarriages as 36.4 +/-3.6% (63/173) and for stillbirths/early death as 4.6 +/- 31.6% (8/173) were obtained. The risk figures for unbalanced offspring after 3:1 disjunction were calculated as 7.7 +/- 7.45 (9/13). CONCLUSIONS: 1. Risk figures for different pregnancy outcomes are differ among particular forms of pathology. 2. Probability rate for unbalanced progeny at birth was calculated as a medium risk and similar values for carriers of different segments of 13q were obtained. 3. Probability rate for miscarriages was high but risk for stillbirths/early deaths of newborn was low. 4. No differences in values of rate for particular forms of pathology were found for maternal and paternal carriers of RCT-13q.

Structural autosomal imbalance and oesophageal defects: addendum to the article by Felix et al. (2007).

Information about approximately 25 additional cases of oesophageal defects in patients with structural autosomal imbalance (in addition to 30 cases already mentioned in the article by Felix et al.) may facilitate search for the genes responsible for these defects.

Distal trisomy 10q and limb defects.

Analysis of the literature showed that hypoplasia (or aplasia) of tibiae was found at least in six persons with trisomy 10q25.2-qter. Therefore, these defects should be considered as a characteristic manifestation of the distal trisomy 10q. In most of these patients, tibial abnormalities were associated with other defects of the lower extremities (hypoplastic femora, ectrodactyly, preaxial polydactyly). Upper limbs were affected in one patient (as well as in her sib without tibial defects). Most likely, segment 10q25.2-qter contains a gene which (when triplicated) leads to maldevelopment of the limbs, and tibial malformations are only one manifestation of this field defect.