We report a rare case of recurrent trisomy 21 caused by an isochromosome 21q and what is very likely to be maternal germ-line cell mosaicism. Over 90% of cases of rob(21;21) reported in the literature are due to an isochromosome 21q, with a risk of recurrence of more than 10%.

We describe a trisomy 21 with a small supernumerary marker chromosome (sSMC) derived from chromosomes 13/21 and 18 in which the karyotype was 48,XY,+der(13 or 21)t(13 or 21;18)(13 or 21pter→13q11 or 21q11.1::18p 11.21→18pter),+21. Of the 35 case reports in the literature for a karyotype 48,XN,+21,+mar, in only 12 was the origin of the sSMC determined by fluorescence in situ hybridization (FISH)...

Isochromosome involving the long arm of X chromosome is a rare structural rearrangement of the X chromosome, leading to Gonadal dysgenesis. These patients present as phenotypic females with amenorrhea and growth failure. Often other associated features like endocrine abnormalities and skeletal deformities are found. They are chromatin positive cases and are only diagnosed by karyotyping. Hashim...

The phenotype of structural chromosome 18 mutations is highly heterogenous, clinical manifestations may range from mild to severe, they have been widely studied in the literature, however, there are few cases where two or more present same individual, reports these alterations caused by a maternal pericentric inversion and diagnosed prenatally even rarer. Affected individuals generally characte...

Deletions of the short arm of chromosome 18 have been well-described in case reports. However, the utility of these descriptions in clinical practice is limited by varied and imprecise breakpoints. As we work to establish genotype-phenotype correlations for 18p-, it is critical to have accurate and complete clinical descriptions of individuals with differing breakpoints. In addition, the develo...

OBJECTIVE The deletion of the short arm of chromosome 18 is thought to be one of the rare chromosomal aberrations. Here, we report a case to review this disease. CASE REPORT The proband is a five-and-a-half-year-old girl who has had phenotypes manifested mainly by ptosis, broad face, broad neck with low posterior hairline, mental retardation, short stature, and other malformations. Chromosoma...

Partial trisomy 2p is a rare but relatively well-defined syndrome with distinctive clinical features, including marked psychomotor delay, dysmorphic face, and congenital heart disease. The phenotype of trisomy 18p is variable, from normal appearance to moderate mental retardation. Most cases of trisomy 2p and trisomy 18p result from the inheritance of an unbalanced segregant from a balanced par...

We report on the prenatal diagnosis, genetic studies, and pathology of a case with de novo isochromosome 13q. A 31-year-old primigravida was referred for genetic counselling at 26 weeks' gestation due to the sonographic findings of intrauterine growth retardation and microcephaly. Level II ultrasonograms further demonstrated alobar holoprosencephaly, hypotelorism, polydactyly, a ventricular sep...