Tay-Sachs disease with atypical chronic course and limited brain storage: alpha-locus hexosaminidase genetic compound.

A 19-year-old Irish-Jewish male had a slow neurologic regression starting at age 4 1/2 years with stuttering. The chronic course resembled that of Spielmeyer-Vogt (juvenile ceroid-lipofuscinosis) disease. The brain was atrophic with neuronal losses and huge compound inclusions in the remaining neurons. Lipid NANA was within normal limits in gray and white matter and GM2 gangliosides were moderately elevated at 11.5% lipid NANA. Beta-hexosaminidase A activity was reduced, secondary to a compound mutation at the alpha-locus. Lysosomal hydrolase activities and lipid composition showed nonspecific abnormalities. Exhaustive tissue extraction ruled out the possibility of tightly bound gangliosides to account for the relatively low GM2 ganglioside concentration. The extract contained unidentified chromogenic substances interfering with the resorcinol reaction. The similarly affected patient's sister lived to age 26 years and her brain was even more atrophic. No biochemical abnormality to account for progressive neuronal losses and relative lack of GM2 ganglioside storage was found.

The Prader-Willi syndrome: a study of 40 patients and a review of the literature.

Forty patients with the Prader-Willi syndrome have been examined. The typical features begin in gestational life with poor fetal vigor and difficulties with birth and post-partum feeding. The classical features of hypotonia, small hands and feet, cryptorchidism can be identified at this time. The delayed milestones, mental retardation and obesity become more prominent later. The average height of the patients in this series who were admitted to the Clinical Study Center was 149 cm and their weight was 114 kg. The weight and height curves show that Prader-Willi individuals are consistently shorter and heavier than normal children. Tests of endocrine function showed normal glucose tolerance. Insulin secretion was increased in relation to obesity. The rise in growth hormone (hGH) after injecting insulin to induce hypoglycemia and after the infusion of arginine was comparable to other obese individuals but was low in comparison to normal weight subjects. There was no rise in growth hormone with L-dopa administration, but there was a rise in hGH with the administration of 2-deoxy-D-glucose. The hypoglycemia produced by insulin was greater in the Prader-Willi patient than in obese controls. The rise in TRH (thyrotropin-releasing hormone) following the injection of TSH (thyrotropin stimulating hormone) was greater in the Prader-Willi patients than in the obese controls. Hypogonadism was routine in this series, and the response to LRH (luteinizing releasing hormone) was absent in all tested subjects. Treatment with clomiphene for 30 to 90 days significantly increased the response to LRH in three adult individuals who had not been treated with gonadal steroids previously and who were hypogonadal. Rectal temperature declined in three of the five Prader-Willi patients during exposure to an ambient temperature of 4 degrees C, but none of the three obese controls showed a decline. Food intake averaged 5167 kcal/d when six patients were given trays containing more food than they could eat. Food intake was not reduced when tryptophan was added to the diet. Salivary secretion was reduced in the Prader-Willi patients. A number of pulmonary function tests were significantly reduced in the study patients compared to obese or normal weight controls. The anatomic findings in four autopsied patients with the Prader-Willi syndrome showed no significant differences from those of obese subjects without this syndrome. The chromosomal pattern showed a deletion or translocation at chromosome 15 in 3 of 12 patients in whom this test was performed. These findings in 40 patients with the Prader-Willi syndrome have been compared with the information contained in 159 reports published in the medical literature.

Normal superoxide dismutase-1 (SOD-1) activity with deletion of chromosome band 21q21 supports localization of SOD-1 locus to 21q22.

The gene for superoxide dismutase-1 (SOD-1) is clearly on chromosome 21, although there is disagreement on the precise band location of SOD-1 on the long (q) arm of number 21. We report a patient with normal superoxide dismutase-1 (SOD-1) activity and an interstitial deletion of chromosome 21 resulting in monosomy for band q21. His phenotype is characterized by moderate mental retardation, a long narrow face, high and arched palate, cardiac murmur, undescended testes, and long hyperflexible extremities. The normal SOD-1 activity supports localization of this enzyme to 21q22.1.

Familial Y-autosome translocation in two unrelated girls.

Two unrelated girls presenting with developmental delay were found to have familial Y-autosome translocations. The first had a Y;15 and the second a Y;22 translocation, involving only the Y heterochromatin on the basis of Q, C, SS, distamycin A and DAPI techniques. The first patient died of a medulloblastoma and at autopsy was found to have an adrenal neuroganglioma. The Y-autosome translocations in the affected patients were identical to those in their respective normal fathers (who had normal Y chromosomes as well). The absence of detectable translocated euchromatin from the subcentromeric region of the Y chromosome is consistent with normal female external genitalia and the absence of germ cell tumors in both patients. Whether the nongonadal neoplasias and hypoplastic uterus and ovaries in the first patient were related to the Y;15 translocation remains uncertain.

Balanced reciprocal (X;9) translocation in a girl with primary amenorrhea.

An 18-year-old girl with an X-autosome translocation t(X;9)(q22;q12) had primary amenorrhea without other manifestations of the Turner syndrome. X-replication and GALT activity studies showed that both of the two translocated X fragments and adjacent autosomal segments are active. An explanation is offered to account for the relationship between the abnormal karyotype and the phenotype. It is suggested that a position effect and/or an effect exerted between reactivation of the X chromosome and oocyte meiosis may be important in the pathogenesis of the amenorrhea.

Ketonic diet in the management of pyruvate dehydrogenase deficiency.

Two brothers, aged 11 years 6 months and 2 years 3 months, with psychomotor and growth retardation, episodes of weakness, ataxia, ophthalmoplegia, and elevated levels of blood pyruvate were shown to have a deficiency in the pyruvate dehydrogenase complex (PDH). When they ate a diet high enough in fats to cause ketonemia but not acidosis, there was a fall in blood pyruvate levels, a decrease in the frequency and severity of the episodes of neurological deterioration, an increased rate of growth and development in the younger brother, and increased strength and endurance in the older one. The possibility of dietary treatment makes the early diagnosis of PDH deficiency more important. Determination of blood pyruvate and lactate levels following a standard glucose meal (glucose-pyruvate test) appears to be the most reliable screening test for this condition.