This study aimed to compare two staining methods for detecting nucleolar organizing regions (NOR) of acrocentric chromosomes in the Cytogenetics Laboratory of INMP (“Instituto Nacional Materno Perinatal”), Lima, Peru.  A total of 60 metaphases with normal karyotypes were analyzed, of which 30 were stained for each method: Kodama et al. and Howell & Black, respectively. The recognition efficiency and staining intensity of these regions were evaluated by each technique based on the count of NORs Ag (+); Likewise, the staining and integrity of the chromosomes were evaluated and the differences between these two methods were established. No significant differences were found regarding the number of stained regions with both techniques; however, in staining intensity and chromosomal quality, the Howell & Black method was superior. It is concluded that the Howell & Black metho...

duplicación 4q,We report the case of a newborn with multiple congenital malformations by unbalanced chromosome complement 46,XY,der(20),t(4;20)(q21;q13.1)mat originated by a reciprocal translocation apparently balanced between chromosomes 4 and 20 in the mother who had a karyotype 46,XX,t(4;20)(q21;q13.1) de novo. The proband´s karyotype showed a duplication of the distal segment of the long arm of chromosome 4 (partial trisomy 4q). The phenotype was altered, presenting several craniofacial, and malformations of internal organs that led to his early death. hereditary commitment and to detect posible carriers. The risks also were determined to provide an appropiate genetic counseling.

Medical genetics is rapidly advancing thanks to technologies that accurately define which genes are involved in the development of diseases. Some syndromes occur in the general population, and their diagnosis and treatment are important to provide patients with an adequate care and prognosis. We present the case of a dysmorphic child who was born at 33 weeks of pregnancy by caesarean delivery due to preeclampsia. Cytogenetic analysis showed a heterozygous deletion on the short arm of chromosome 17 (46, XX, del 17p11.2). The diagnosis was complemented by MLPA analysis, which measures the presence/absence of certain genes defined in some syndromes, and confirmed the deletion of 2.1 megabases of DNA, including the RAI1 gene, responsible for the Smith-Magenis syndrome.

The partial trisomy 4p, usually originated from translocations between chromosome 4 and other non-homologous chromosomes or pericentric inversion of chromosome 4, causing abnormal chromosome gametes between normal and the inverted one, yielding a recombinant chromosome duplication can carry small ami segments (4p) or the long arm (4q) the latter being non-viable. The phenotypic characteristics of this condition present with severe mental retardation, delayed psychomotor development, craniofacial anomalies, strabismus, musculoskeletal defects, heart defects, cryptorchidism and micropenis. We describe the case of a 1-year 6-month child with delay in psychomotor development and dysmorphic features, having a recombinant 4p duplication of paternal origin. It is the first case of duplication 4p found in our institution due to hereditary, it is necessary to perform counseling to parents and mon...

Chromosomal deletions are structural abnormalities that cause loss of genomic material, depending on itslength they use to generate several disabling genetic conditions. Interstitial deletion of chromosome 17 shortarm in 17p11.2 region is related to the appearance of phenotypic characteristics related to a genetic conditionknown as Smith-Magenis syndrome. This deletions spans in a range between <1.5 and 9 Mb, shows somefeatures as craniofacial dysmorphia, delayed psychomotor development, speech problems, sleep disorders,limb abnormalities, malformations of brain, heart and kidney also are expressed. We present a case of a 10monthsold girl with brachycephaly, bulging forehead, sunken eyes, epicanthal folds, malformed ears, shortphiltrum, small mouth and ventriculomegaly. The gir´sl karyotype was 46,XX,del(17)(p11.2), no moleculartests were performed because they were not available, bu...

We describe the case of a male term neonate with psychomotor development anomalies, craniofacial defects, limbs and genital anomalies, born at Instituto Nacional Materno Perinatal in which an interstitial chromosomal deletion was found in the long arm of chromosome 4. The karyotype of the newborn was 46, XY, del (4) (q22q25) de novo. The phenotypic traits observed in the propositus were compatible with 4q- syndrome.

Trisomy 8 is an uncommon anomaly in neonates, frequently being a lethal condition among individuals with pure trisomiclines and more tolerable in mosaics cases. This aneuploidy is mainly characterized by a moderate - severe intellectual deficitand poor motor coordination. Affected individuals presents craniofacial malformations, prominent forehead, arched palate,deformed ears with low implantation, elongated trunk, reduced motility, articular defects and deep plantar grooves, which isone of the main characteristics of this condition. Abnormalities of internal organs are of varying severity. We present the reportof two cases of trisomy 8 or Warkany syndrome 2 born at Instituto Nacional Materno Perinatal.