Toshihisa Okada

Possible mapping of the gene for transient myeloproliferative syndrome at 21q11.2

SummaryThe parental origin of the extra chromosome 21 was studied in 20 patients with trisomy 21-associated transient myeloproliferative syndrome (TMS) using chromosomal heteromorphisms as markers; this was combined with a study of DNA polymorphisms in 5 patients. Of these, 10 were shown to result from duplication of a parental chromosome 21, viz., maternal in 8 and paternal in 2. A patient with Down syndrome-associated TMS had a paracentric inversion in two of his three chromosomes 21 [47,XY,-21, +inv(21)(q11.2q22.13)mat, +inv(21)(q11.2 q22.13)mat). These findings support our hypothesis of “disomic homozygosity” of a mutant gene on chromosome 21 in 21-trisomic cells as being a mechanism responsible for the occurrence of TMS. The finding also suggests that the putative TMS gene locus is at either 21q11.2 or 21q22.13, assuming that the gene is interrupted at either site because of the inversion. The study of 5 TMS patients using DNA polymorphic markers detected a cross-over site on the duplicated chromosomes 21 between 21q11.2 (or q21.2) and 21q21.3 in one patient, and a site between 21q21.3 and q22.3 in another patient, evidence that confined the gene locus to the 21cen-q21.3 segment. These findings suggest that the putative TMS gene is located at 21q11.2. The extra chromosome 21 in the latter two TMS patients probably resulted from maternal second meiotic non-disjunction, in view of the presence of recombinant heterozygous segments on their duplicated chromosomes 21.

Young‐Simpson syndrome: Further delineation of a distinct syndrome with congenital hypothyroidism, congenital heart defects, facial dysmorphism, and mental retardation

Young-Simpson syndrome is a rare congenital disorder, characterized by congenital hypothyroidism, congenital heart defects, facial dysmorphism, cryptorchidism in males, hypotonia, mental retardation, and postnatal growth retardation. We describe the cases of a 5-year-old boy and a 7-year-old girl with a similar constellation of symptoms and compared them with previously reported patients.

Monthly Urinary Gonadotropin and Ovarian Hormone Excretory Patterns in Normal Girls and Female Patients with Idiopathic Precocious Puberty

To identify the developmental changes in monthly urinary gonadotropin and ovarian hormone excretion, consecutive 30-d first morning void urinary specimens were collected from 36 normal girls, one normal woman, and 15 female patients with idiopathic precocious puberty. Of these children, three normal girls and three patients with precocious puberty volunteered to collect these specimens on 2-3 occasions over a time interval of 0.5-3.2 y. When sampled, six were early prepubertal, nine late prepubertal, eight early pubertal, eight mid-pubertal, and eight late pubertal normal girls, and six were early pubertal and 14 mid-pubertal patients with precocious puberty. The mean level of monthly urinary LH, FSH, and total estrogen excretions increased with pubertal maturation. In prepuberty, the mean LH level was lower than the mean FSH level, and neither showed significant episodic fluctuations. In early puberty, mean FSH levels increased with remarkable fluctuations, and mean LH levels were low with few variations in the course of a month. At the onset of puberty, gonadotropin excretory patterns underwent specific changes, showing at the same time periodically and every other day fluctuating patterns. Urinary total estrogen and pregnanediol excretion fluctuated independently from these periodic variations in urinary gonadotropins. These patterns were observed in six out of 16 patterns in normal pubertal girls and 10 out of 20 patterns in precocious puberty. Once the urine LH level exceeded the urine FSH level, however, these periodic variations disappeared. The cycle of a normal postmenarcheal girl aged 14 y showed a pattern similar to that of a normal adult. In patients with precocious puberty, the hormonal patterns were similar to those of sexual stage-matched normal girls.