Prenatal diagnosis of monosomy 1p36: a focus on brain abnormalities and a review of the literature.

Monosomy 1p36 is an increasingly recognized chromosomal anomaly. We describe two patients with monosomy 1p36 who had brain abnormalities detected on prenatal ultrasound. The first patient was ascertained prenatally with ultrasound abnormalities, including ventriculomegaly, a single umbilical artery, a unilateral club foot, a ventricular septal defect, and intra-uterine growth retardation.

Clinical and molecular cytogenetic characterization of four patients with unbalanced translocation der(1)t(1;22)(p36;q13).

Deletion of chromosome 1p36 is the most commonly observed terminal deletion in humans with a frequency of 1 in 5,000 in the general population. In contrast, 22q13 duplications are rare and only a few cases have been reported. Unbalanced translocations resulting in monosomy 1p36 and a trisomy of 22q13.

Unexpected complexity at breakpoint junctions in phenotypically normal individuals and mechanisms involved in generating balanced translocations t(1;22)(p36;q13).

Approximately one in 500 individuals carries a reciprocal translocation. Balanced translocations are usually associated with a normal phenotype unless the translocation breakpoints disrupt a gene(s) or cause a position effect. We investigated breakpoint junctions at the sequence level in phenotypically normal balanced translocation carriers.

Monosomy 1p36 deletion syndrome.

Monosomy 1p36 results from a heterozygous deletion of the most distal chromosomal band on the short arm of chromosome 1. Occurring in approximately 1 in 5,000 live births, monosomy 1p36 is the most common terminal deletion observed in humans. Monosomy 1p36 is associated with mental retardation, developmental delay, hearing impairment, seizures, growth impairment, hypotonia, and heart defects.