The natural history of classic galactosemia: lessons from the GalNet registry.

BACKGROUND: Classic galactosemia is a rare inborn error of carbohydrate metabolism, caused by a severe deficiency of the enzyme galactose-1-phosphate uridylyltransferase (GALT). A galactose-restricted diet has proven to be very effective to treat the neonatal life-threatening manifestations and has been the cornerstone of treatment for this severe disease. However, burdensome complications occur despite a lifelong diet. For rare diseases, a patient disease specific registry is fundamental to monitor the lifespan pathology and to evaluate the safety and efficacy of potential therapies. In 2014, the international Galactosemias Network (GalNet) developed a web-based patient registry for this disease, the GalNet Registry. The aim was to delineate the natural history of classic galactosemia based on a large dataset of patients. METHODS: Observational data derived from 15 countries and 32 centers including 509 patients were acquired between December 2014 and July 2018. RESULTS: Most affected patients experienced neonatal manifestations (79.8%) and despite following a diet developed brain impairments (85.0%), primary ovarian insufficiency (79.7%) and a diminished bone mineral density (26.5%). Newborn screening, age at onset of dietary treatment, strictness of the galactose-restricted diet, p.Gln188Arg mutation and GALT enzyme activity influenced the clinical picture. Detection by newborn screening and commencement of diet in the first week of life were associated with a more favorable outcome. A homozygous p.Gln188Arg mutation, GALT enzyme activity of ≤ 1% and strict galactose restriction were associated with a less favorable outcome. CONCLUSION: This study describes the natural history of classic galactosemia based on the hitherto largest data set.

Intrafamilial oocyte donation in classic galactosemia: ethical and societal aspects.

Classic galactosemia is a rare inherited disorder of galactose metabolism. Primary ovarian insufficiency (POI) with subfertility affects > 80% of female patients and is an important concern for patients and their parents. Healthcare providers are often consulted for subfertility treatment possibilities. An option brought up by the families is intrafamilial oocyte donation (mother-to-daughter or sister-to-sister). In addition to POI, galactosemia patients can also present varying cognitive and neurological impairments, which may not be fully clear at the time when mother-to-daughter oocyte donation is considered. Ethical and societal aspects arise when exploring this option. This study aimed to provide guidance in aspects to consider based on the views of different groups involved in the oocyte donation process. A qualitative study using in-depth semi-structured interviews with > 50 participants (patients, family members, and healthcare providers) was conducted. From these interviews, themes of concern emerged, which are illustrated and reviewed: (1) family relations, (2) medical impact, (3) patients' cognitive level, (4) agreements to be made in advance and organization of counseling, (5) disclosure to the child, and (6) need for follow-up. We conclude that discussing and carrying out intrafamilial oocyte donation in galactosemia patients requires carefully addressing these themes. This study adds value to the already existing recommendations on intrafamilial oocyte donation in general, since it highlights important additional aspects from the perspectives of patients and their families.