Contributed by: Dr Dhanya Lakshmi N
Department of Medical Genetics, Kasturba Medical College, Manipal, Karnataka, India
  The proband has biallelic disease-causing variants in the GM2A and in NIPAL4 genes, causing GM2 gangliosidosis AB variant (MIM #272750) and autosomal recessive congenital ichthyosis 6 (MIM #612281) respectively. The parents are heterozygous carriers for both the variants. The family wants to know the chance of having an unaffected child in the subsequent pregnancy. What is the chance of this family having a child without ichthyosis or GM2 gangliosidosis?  

Please send your responses to

  Click here to submit you answer  
Answer to PhotoQuiz 43
Inherited Systemic Hyalinosis/ Hyaline Fibromatosis Syndrome (OMIM # 228600)
Hyaline fibromatosis syndrome is an autosomal recessive disorder characterized by abnormal growth of hyalinized fibrous tissue usually in the subcutaneous regions of the face, neck, hands, legs and feet, which appear as fleshy nodules. The condition can have variable severity and the severe form of the disorder which presents in infancy called 'infantile systemic hyalinosis' can have additional systemic involvement in the form of chronic diarrhea and predisposition to infections, which can lead to death in infancy or early childhood. They can also have gingival hypertrophy, progressive joint contractures and joint pains, and osteopenia. It is an autosomal recessive disorder caused by biallelic mutations in the ANTXR2 (anthrax toxin receptor 2) gene on chromosome 4q21, which codes for a protein that plays an important role in basement membrane matrix assembly and endothelial cell morphogenesis.
Correct responses were given by:
1. Ravneet Kaur, New Delhi
2. Jayaprakash P, Kottayam
3. Diksha Shirodkar, Bengaluru
4. Ashka Prajapati, Ahmedabad
5. Naresh Tayade, Amravati
6. Kanika Singh, New Delhi
7. Beena Suresh, Chennai
8. Meenakshi Bhat, Bengaluru
9. Anupriya Kaur, Chandigarh
10. Lekshmi S Nair,Hyderabad
11. M L Kulkarni, Davangere
12. Komal Uppal, Nalgonda
13. Jayarekha Raja, Chennai
14. J P Soni, Jodhpur