Diagnosis of two neonates with galactosemia by using next generation sequencing / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To explore the genetic basis of two neonates suspected for galactosemia.</p><p><b>METHODS</b>Next generation sequencing(NGS) was used to screen the whole exome of the neonates. Suspected mutation was validated by PCR and Sanger sequencing. Potential impact of novel mutation was predicted by using PolyPhen-2, MutationTaste and SIFT software.</p><p><b>RESULTS</b>Both neonates harbored compound heterozygous mutations of the GALT gene inherited from their parents. One has inherited two novel mutations c.564G>C(p.Q188H) and c.116A>T(p.D39V) respectively from his father and mother. The other has inherited mutations c.754C>T(p.Q252X) and c.904+1G>T from her father and mother, respectively.</p><p><b>CONCLUSION</b>The galactosemia in the two neonates may be attributed to compound heterozygous mutations of the GALT gene. This is the first domestic report of using the NGS for the diagnosis of galactosemia.</p>

A Case of Classical Galactosemia caused by Compound Heterozygous Mutations of the GALT Gene

Classical galactosemia is an autosomal recessive disorder of galactose metabolism, caused by a deficiency of the enzyme galactose-1-phosphate uridyltransferase (GALT). Buildup of galactose-1-phosphate is toxic at high levels and can damage the liver, brain, eyes, and other vital organs. The case presented here was that of an 11-day-old female infant who had elevated galatose levels upon initial neonatal screening test with persistent cholestatic jaundice, coagulopathy, and hepatomegaly. The patient was transferred due to aggravation of clinical symptoms including bleeding and jaundice. She had a delayed galactose free diet because of an inappropriate diagnosis. We quickly provided her with a lactose/ galactose-restricted diet as per her final diagnosis. Clinical and laboratory results were improved after a few days of treatment. For confirmatory testing for classical galactosaemia, we simultaneously analyzed for GALT enzyme activity and allele-specific PCR/fragments for seven mutations and two polymorphisms in the GALT gene. We were able to find several GALT-deficient and compound heterozygous mutations of the GALT gene.

Galactosemia / 한양의대학술지

Galactosemia, a term that denotes the presence of galactose in the blood, is the name of rare inborn error of galactose metabolism due to a deficiency of the enzyme galactokinase (GALK), galactose-1-phosphate uridyltransferase (GALT) and uridine diphosphate-galactose 4-epimerase (GALE). GALT deficiency is the most common and shows the most severe clinical manifestation, including hepatomegaly, cataracts, and mental retardation. The main symptom of GALT deficiency is juvenile cataracts. GALE deficiency has two different forms; benign and severe forms. The benign form has no clinical significance, however, the severe form shows the same clinical manifestations as those of GALT deficiency.

Analysis of the Galactose-1-Phosphate Uridyltransferase (GALT) Gene in a Duarte Variant/classical Galactosemia (D/G) Compound Heterozygote / 대한소아소화기영양학회지

Galactosemia is a rare autosomal recessive disorder caused by the deficiency of galactose-1-phosphate uridyltransferase (GALT) enzyme activity. Classic galactosemia (G/G) is due to severe GALT deficiency in the presence of a GALT gene mutation, whereas Duarte variant (D/D) has 50% of normal GALT activity and benign clinical course. The D2 allele of Duarte variant is linked to a promoter deletion 5' to the translation start site (-119 to -116 delGTCA) in addition to N314D. So, Duarte variant/classical galactosemia (D/G) compound heterozygotes have relatively mild clinical manifestation than classical galactosemia and can be differentiated from classical galactosemia or Duarte variant by mutational analysis. We report a case of D/G galactosemia compound heterozygote proven by the reduction of GALT enzyme activity in erythrocytes and mutation analysis of GALT gene, which revealed N314D polymorphism and -119 to -116 delGTCA.

Galactosemia: a treatable metabolic disorder

Case Reports: A term male baby was delivered normally in hospital with Apgar score 10/10 at 5 minutes, weighting 3200 grams and no congenital anomaly was apparent. Baby was sent home same day. He was brought on 5th day with complaint of jaundice. Total Serum bilirubin was 21.0-mg% with predominant indirect hyperbilirubinemia. No evidence of ABO, Rh incompatibility, glucose-6-phosphate dehydrogenase[G6PD] deficiency or any other cause of jaundice detected at this stage. He was admitted in hospital and phototherapy was started. Baby remained active, aferbile, feeding well during hospital stay. Serum bilirubin dropped to 13.0-mg% on 10th day and was discharged in satisfactory condition. But he was readmitted after one day with complaint of poor feeding, drowsiness, hypothermia and lethargy. With clinical impression of neonatal sepsis, injection ceftriaxone and amikacin were started empirically. Mild jaundice was still present. Investigations revealed hemoglobin [Hb] 13.0 gm%, total leukocyte count[TLC] 2800/mm3, platelets 40,000/mm3, blood glucose 60mg% and serum bilirubin 8.0mg%. Condition of baby improved after 24 hours. He became active and started taking feeds. Blood culture revealed growth of E. coli, sensitive to above antibiotics. Antibiotics were continued for 12 days and baby was discharged. On follow up after 10 days at 01-month of age, baby was quite pale looking, deeply jaundiced and not gaining weight. He weighed only 3.3 kg at 35 days of age. Investigations revealed Hb: 8.0 gm%, serum bilirubin 18.0 mg%, Alanine transferase[ALT] 190iu/l, Alkaline phosphatase 1056 u/l with predominant indirect hyperbilirubinemia. Urine examination revealed no abnormality. Ultrasonography[USG] of abdomen revealed mild hepatomegaly with diffuse increased echogenecity. New clinical finding was bilateral lenticular haze [oil droplet type], confirmed by ophthalmologist. Urine for reducing substances was repeated which was strongly positive with Benedict's solution but negative with glucostix. Keeping in mind the possibility of glactosemia, breast-feeding was stopped and replaced with Soy based milk. Red cell concentrate was also transfused and further investigations were done to rule out other causes of persistent indirect hyperbilirubinemia. On induction of lactose free milk, jaundice remarkably regressed in about one week time. Lenticular opacities almost completely disappeared and LFTS became normal in about one month time. Baby is on regular follow up. He is now one year old weighing 9.5 kg and achieving developmental milestones normal for age

Diagnóstico bioquímico de 2 niños con galactosemia / Biochemical diagnosis of two children with galactosemia

Se presenta un estudio bioquímico realizado en el Centro Nacional de Genénica Médica a 2 niños remitidos por sospecha clínica de padecer galactosemia. Se realizó la cromatrografía en capa fina para la detección de carbohidratos en orina, y se halló una banda al nivel de galactosa. Posteriormente se procedió a la cuantificación del metabolito en orina y suero, y se detectó éste elevado de ambos fluidos. El diagnóstico bioquímico final consistió en comprobar la deficiencia de la enzima galactosa-1-fosfato uridil transferasa eritrocitaria por el método espectrofotométrico; se comprobó también el carácter de portadores del gen deficiente en los padres de ambos niños

A Dactylium dendroides morphological mutant defective in D-galactose metabolism

1. A morphological mutant of the mold Dactylium dendroides was and the phenotype characterized as D-Gal-and L-Ara-. 2. The transport system for D-galactose seemed to be inducible in wild type and mutant and was altered in the mutant. 3. Galactose-1-P- uridylyl transferase activity was absent in the mutant. 4. The levels of intracellular galactose oxidase activity were similar in the wild type and in the mutant, theraby excluding a possible participation of this enzymes in glactose catabolism inthe mold. 5. The low level of galactose oxidase activity found in the extracellular medium indicates a defect in galactose oxidase secretion by the mutant