Yoshikazu Kuroki

A new malformation syndrome of long palpebralfissures, large ears, depressed nasal tip, and skeletal anomalies associated with postnatal dwarfism and mental retardation

Five unrelated patients with a previously unrecognized mental retardation malformation syndrome are presented. Clinical features common to them include moderate mental retardation, postnatal dwarfism, susceptibility to infection in infancy, and peculiar craniofacial dysmorphia characterized by long palpebral fissures, high-arched and abnormal eyebrows, heavy and long eyelashes, large ears, short nasal septum and/or depressed nasal tip, and cleft palate. Other anomalies are stubby fingers, deformed vertebra and other bone and joint anomalies, and abnormal dermatoglyphics. The absence of familial occurrence and of consanguinity suggests some environmental causation, but the possibility of an autosomal dominant or X-linked mode of inheritance remains. Based upon our five patients and other five of Niikawa et al, we propose this syndrome as a new disease entity.

A case of 21q-syndrome with normal SOD-1 activity

SummaryA female infant with del(21)(pter→q22.1-2:) constitution identified by G, Q, and R banding is reported. She had marked mental and physical retardation, generalized hypertonia, microphthalmia with persistent hypoplastic primary vitreous, blepharochalasia, high nasal bridge, micrognathia, malformed ears with preauricular pits, and overlying fingers. The assay for superoxide dismutase-1 (SOD-1) activity in the patient revealed a normal value and it was suggested that the gene locus for SOD-1 in 21q22.2→qter is not compatible with the presence of the gene dosage effect in the monosomic state.

Precocious puberty in Kabuki makeup syndrome

features present in these two siblings; however, they lack microcephaly, cutaneous dimples, renal and geni ta l anomalies, and immunoglobul in A deficiency, character is t ics commonly seen in these patients?,13.14 Fur thermore , it is unlikely for a couple to have two children with chromosomal abnormal i t ies unless one of the parents carries a chromosomal t ranslocat ion, which has not been found in this case. The rare possibility of gonadal mosaicism cannot be excluded. Considera t ion of the possible genetic implications for other such families provides a basis for appropriate genetic counseling and management .

The “happy puppet” syndrome in two siblings

SummaryTwo siblings with the “happy puppet” syndrome are presented. Their clinical features are quite similar and closely resemble those of previously reported cases. These features include severe mental retardation, epileptic seizures, easily provoked and prolonged paroxysms of laughter, atactic jerky movements, hypotonia, large mandible with prognathia, and 2–3 cps spike and wave activity in the EEG. The occurrence of this syndrome in the two siblings suggests a genetic etiology possibly as an autosomal recessive trait.

Standard growth curves for Japanese patients with Prader‐Willi syndrome

We constructed the standard growth (length/height and weight) curves for Japanese individuals with Prader-Willi syndrome (PWS). Crude height and weight data were collected from 153 males and 99 females with the syndrome, and the collected data were arranged by a mathematical method to construct the curves. Height growth patterns were quite different between PWS and normal children. Mean height of individuals with the syndrome by puberty is -2 SD for normal children, and it drops off far below -2 SD value after puberty. Final mean height is 141.2 +/- 4.8 cm for females (n = 13) and 147.7 +/- 7.7 cm for males (n = 17), showing 15.8 and 21.9 cm below the average height for normal Japanese girls and boys, respectively. Thus, the degree of shortness is more pronounced in male than in female patients. There was no difference in height between those with chromosome 15q deletion and those without. Mean weight at birth of girls (n = 88) and boys (n = 131) were 2.70 +/- 0.45 Kg and 2.62 +/- 0.47 Kg, respectively. These values were smaller than those for normal neonates (P < 0.05, t-test). The weight of PWS children was under the mean value for normal infants by age 2 years, but gradually increase above the mean values for normal children around ages 2-4 years. Overweight in both males and females becomes obvious during prepuberty. Growth patterns are not different between Japanese and Caucasian children with the syndrome. Short stature is more prominent in boys of both ethnic groups, whereas the degree of overweight appears much more severe in Caucasians.

Partial trisomy of 11 and 22 due to familial translocation t(11;22) (q23;q11), inherited in three generations

SummaryA 1-year-old girl with partial trisomy of 11 (q23→qter) and 22 (pter→q11) is presented. She had severe mental retardation, cleft palate, congenital heart disease, congenital dislocation of the hip, and other anomalies.The extra acrocentric chromosome was identified as der(22),t(11;22) (q23;q11) from a familial translocation and by G-and R-banding methods. The mother and the maternal grandfather were carriers of balanced rcp(11;22) (q23;q11) translocations.The possible relations between phenotypic features and the karyotypes of partial trisomy 11 and 22 are discussed.

A case of r(21) with stigmata of atypical Down syndrome

SummaryA case of r(21) with stigmata of atypical Down syndrome is presented. Karyotype of the proposita was determined as 45,XX,-21/46,XX,-21, +r(21)/47,XX,-21,+r(21),+(21). Most ring chromosomes showed double-sized ring chromosomes, which were trisomic for 21p11-21q22.3 and monosomic for 21q22.3-qter. SOD-1 activity revealed only slight elevation. The mechanism of ring formation is discussed.

Ring 18 Mosaicism in Identical Twins

SummaryMale identical twins with r(18)/normal mosaicism are reported. Twin 1 has the characteristic manifestations of the r(18) syndrome, but twin 2 shows a normal phenotype. Cytogenetic study of cultured lymphocytes revealed that the proportions of r(18) are 19.7% and 19.2%, respectively. However in the fibroblast cultures, the ring is observed in 51% of cells in twin 1 and in 0% in twin 2. The mechanism of the occurrence of the discrepant phenotypes in the twins is discussed.

HRAS mutants identified in Costello syndrome patients can induce cellular senescence: possible implications for the pathogenesis of Costello syndrome

Costello syndrome (CS) is a congenital disease that is characterized by a distinctive facial appearance, failure to thrive, mental retardation and cardiomyopathy. In 2005, we discovered that heterozygous germline mutations in HRAS caused CS. Several studies have shown that CS-associated HRAS mutations are clustered in codons 12 and 13, and mutations in other codons have also been identified. However, a comprehensive comparison of the substitutions identified in patients with CS has not been conducted. In the current study, we identified four mutations (p.G12S, p.G12A, p.G12C and p.G12D) in 21 patients and analyzed the associated clinical manifestations of CS in these individuals. To examine functional differences among the identified mutations, we characterized a total of nine HRAS mutants, including seven distinct substitutions in codons 12 and 13, p.K117R and p.A146T. The p.A146T mutant demonstrated the weakest Raf-binding activity, and the p.K117R and p.A146T mutants had weaker effects on downstream c-Jun N-terminal kinase signaling than did codon 12 or 13 mutants. We demonstrated that these mutant HRAS proteins induced senescence when overexpressed in human fibroblasts. Oncogene-induced senescence is a cellular reaction that controls cell proliferation in response to oncogenic mutation and it has been considered one of the tumor suppression mechanisms in vivo. Our findings suggest that the HRAS mutations identified in CS are sufficient to cause oncogene-induced senescence and that cellular senescence might therefore contribute to the pathogenesis of CS.

A case of 9p- syndrome

SummaryAn 8-month-old female child with the 9p- karyotype: 46,XX,del(9) (p22) is presented, being the first case from among Oriental people. She has many clinical featues similar to those described in Caucasian cases.