Sayee Rajangam

Consanguinity and chromosomal abnormality

BACKGROUND : Consanguinity is defined as the marriage between close relatives. The deleterious effects associated with consanguinity may be caused by the expression of rare recessive genes inherited from common ancestors. AIMS AND OBJECTIVES : The present study was undertaken to analyze the effect of consanguinity on chromosomal abnormality (CA). METHODS AND MATERIALS : During last 6 years period, a total of 1465 cases with suspected genetic etiology like bad obstetric history, mental retardation, multiple congenital anomalies, Down syndrome, primary amenorrhea and primary infertility was referred to Division of Human Genetics for karyotyping and genetic counseling. The information regarding consanguinity was obtained through pedigree analyzes up to three generations from all the patients. Chi-square test was applied to test the significance. RESULTS : Consanguinity was seen in 427 cases (29.14%), 305 cases were confirmed to have CA, among them 240 (78.7%) had numerical abnormality and 65 (21.3%) had structural abnormality. The presence of consanguinity in CA was seen in 53 cases (17%), including 43 (81.1%) with numerical and 10 (18.9%) with structural abnormality. CONCLUSION : The effect of consanguinity on CA was almost significant ( P

Down syndrome with biparental inheritance of der(14q21q) and maternally derived trisomy 21 : Confirmation by fluorescent in situ hybridization and microsatellite polymorphism analysis

Individuals with translocation Down syndrome (DS) often inherit the rearranged chromosome from a carrier parent. DS due to inheritance of one Robertsonian or derivative (14q21q) from one parent and a second der(14q21q) in addition to a free chromosome 21 from the other parent are rarely documented in liveborn infants. Presented here is such a propositus with DS and with a unique karyotype 45,XY,der(14;21) (p11.1;p11.1)pat,der(14;21)(p11.1;q11.1)mat, +21mat. Using conventional chromosome heteromorphisms, fluorescent in situ hybridization (FISH), and microsatellite polymorphism analyses, we established the biparental origin of the 2 der(14q21q) and the maternal origin of the extra chromosome 21 in the patient. A combination of both cytogenetic and molecular genetic techniques also enabled us to show that the 2 der(14q21q) were not identical by descent and hence the parents were nonconsanguineous. It has been a well-established fact that mothers with Robertsonian translocations have higher risk for nondisjunction than do carrier fathers. Our case, wherein the nondisjunctional event occurred in the mother, even though both parents are carriers of a 14;21 Robertsonian translocation, is yet another example of this.

Ellis—van creveld syndrome

Eleven cases of chondroetodermal dysplasia (Ellis-Van Creveld syndrome) occurring in three pairs of siblings and five isolated cases are described and literature reviewed.

Cytogenetic Analysis in Down Syndrome

Abstract Clinically diagnosed Down syndrome cases are referred for karyotyping and counseling. Data on incidence patterns of the 3 cytogenetic types of Down syndrome from the cases seen during the duration of 35 years is presented. Chromosomes were examined after G-banded technique of peripheral lymphocyte cultures. For each patient, in addition to the detailed case history in the proforma 15 metaphases were examined and in cases of mosaicism, the count was increased to 25 to 50 metaphases for analysis. A total of 874 cases were confirmed to have the karyotype of Down syndrome. 509 were male probands (58.24%) and 365 (41.76%) were female cases. The most common was free trisomy 21 in 759 (86.9%), translocation in 77 (8.8%) and mosaicism in 38 (4.3%) cases. Robertsonian translocation 14;21 (48;62.34%) was prevalent among the 77 cases with translocation and the remaining 29 cases had the translocation of chromosome 21 either to chromosomes 1 (1) or 15(2) or 21 (26). The sex ratio has indicated the prevalence of the males for the total sample (1.41:1) (509: 365) as well as for the 3 basic cytogenetic types of DS. Included in the male trisomy 21 are the 2 cases with Klinefelter syndrome (KFS)(48,XXY+21) and one with de novo Robertsonian translocation between chromosomes 13 and 14.

Bad Obstetric History and Infectious Causes

This article refers to the association beTable I: BOH And Infectious Causes (TORCH) Serial No. Maternal No. of Age Abortions 1 21 3 2 29 2 3 28 3 4 29 6 5 25 2 6 37 4 7 36 6 8 20 3 9 25 3 10 24 3 11 26 2 12 25 4 13 21 2 14 21 2 15 34 4 16 37 3 17 26 4 18 27 3 19 23 3 20 28 8 Mean 27.11 3.30 ±1.66

A Data Profile of Phenotypic Features in 72 Klinefelter Syndrome (KFS) Males

Abstract Klinefelter syndrome phenotype is associated with hypogonadism and infertility that results from 47,XXY or 46,XY/47,XXY karyotype. Men with mosaic status show milder phenotype than those of non-mosaics. The present study aimed to report, a data profile on the observed phenotypic features in 72 cytogenetically confirmed Klinefelter syndrome male gathered from duly filled proforma. The reported phenotype from the literature were categorized into 14 groups (highly arched palate, winged scapula, thin long fingers, flat feet, prognathism, liver cirrohsis, seizures, mental illness, penis, gonads, axillary hair growth, and pubic hair growth, presence of gynaecomastia and semen analysis). The calculated total number of the 14 features multiplied for the 72 samples was 1,008. Of the 1,008 features (14X72), KFS male manifested only 16.56% of abnormal features (167/1,008). Scanty axillary hair growth (25%, 18), scanty pubic hair growth (26.38%, 19), small sized penis (25%, 18), small sized gonads (55.56%, 40), presence of gynaecomastia (45.83%, 33) were of highest percentage. It was noticed that, for the entire sample of 72, the manifestation of the 14 categorised features was only 16.56%, irrespective of the karyotype; out of which, with 47,XXY, the manifestation of the phenotypic features was observed to be highest (18.52%, 153/ 826). The findings confirmed the reported observations that in Klinefelter syndrome, there seemed to be a wide variability in the phenotype.

Dermatoglyphics-Quantitative Analysis in Rheumatoid Arthritis

Abstract Various studies have shown dermatoglyphics as a possible marker and a tool to detect Rheumatoid arthritis. In the present study, quantitative, dermatoglyphic features comprising of ‘total finger ridge count’, absolute finger ridge count’ and ‘a-b ridge count’ was done on 11 males and 25 females in both hands and compared with equal number of controls. A trend towards significance was observed in right hand of male patients with respect to ‘Total finger ridge count’ (Patient 56.09±26.22, Control 35.36±8.9, p = 0.0873, n = 11). On the other hand, female patients showed significance for the right hand for ‘Absolute finger ridge count (Patient = 99±43.75, Control 93.5±42.05, p = 0.0358, n = 22) and in the left hand for the male patients (Patient = 94.27±37.58, Control = 94.27±28.56, p=0.0358, n= 11). Significant values were found in the in left hand for female (Patient 39.2±6.85, Control 38.08±5.07, p = 0.0437, n = 11) and right hand of male patients for ‘a-b ridge count’ (Patient = 73.64± 20.32, Control 38.64±4.10, p = 0.0002, n = 11). The observations of the present study, has suggested, that ‘a-d’ ridge count could be considered as marker for male as well as female patients as the diagnostic tool in linking the rheumatoid arthritis to dermatoglyphics. Further studies are needed on a large scale to confirm.

45,X/47,X,i(X)(q10),i(X)(q10)/46,X,i(X)(q10) Isochromosome Xq in Mosaic Turner syndrome

Abstract A 17-year old female has been referred for karyotyping and genetic counseling. Proband had primary amenorrhea, short stature and poorly developed secondary sexual characteristics. Ultrasound scanning showed hypoplastic uterus and gonadal dysgensis. Chromosomal analysis revealed the mosaic status for the isochromosome formation in the long arm of X, i(Xq). Proband had 3 cell lines. Her karyotype: 45,X(4%)/ 47,X, i(X)(q10), i(X)(q10)(8%)/ 46,X, i(X)(q10)(88%). Proband has expressed X numerical anomaly for the constitutional X structural anomaly. Proband and family were counseled about education, career, appropriate medical management and hormonal therapy.

Partial 1q and 21p trisomies in a male child due to maternal t(1;21).

Proband 7 years old male child referred for cytogenetic investigation revealed 47, XY + der (21), t(1;21) (q 32; q 11) mat.

Congenital Heart Defects and Chromosomal Abnormality

Abstract Chromosomal abnormality is one of the causal factors in the formation of the congenital heart defects. 65 patients (33 male and 32 female) with heart defects were referred for karyotyping and counseling. Chromosomal abnormalities were detected in 27 (41.5%) and 38 had a normal karyotype. Numerical abnormality was found in 21 (77.8%) and structural in 6 (22.2%), numerical was detected in 14 females and 7 males, and structural in 4 female and 2 male patients. Numerical abnormality was one with 47,XX+13; 2 with 45,X and 18 with 47,XX+21 (11) or 47,XY+21(7). Structural abnormality was derivative 9 in 2, deletion 11q, derivative 14, Robertsonian translocation between 14 and 21 and ring 18 mosaicism in one each. Parental origin of the structural abnormality revealed that two were maternal and one was paternal. In the present study, association could be detected between chromosome 21 and the female probands with chromosomal abnormality and heart defects.