Endocrine, nutritional and metabolic diseases
Metabolic disorders
Autosomal recessive
5q33.1
The GM2-gangliosidoses are a group of disorders caused by excessive accumulation of ganglioside GM2 and related glycolipids in the lysosomes, mainly of neuronal cells. GM2-gangliosidosis AB variant is characterized by normal hexosaminidase A (HEXA) and hexosaminidase B (HEXB) but the inability to form a functional GM2 activator complex. The clinical and biochemical phenotype of the AB variant is very similar to that of classic Tay-Sachs disease. [From OMIM]
| Subject ID | Country | Sex | Family History | Parental Consanguinity | HPO Terms | Variant | Zygosity | Mode of Inheritance | Reference | Remarks |
|---|---|---|---|---|---|---|---|---|---|---|
| 272750.1.1 | Saudi Arabia | Female | Yes | Global developmental delay; Hypotonia; H... Global developmental delay; Hypotonia; Hyporeflexia; Seizure; Hyperacusis; Cherry red spot of the macula; Nystagmus; Hepatomegaly; Brain atrophy  | NM_000405.5:c.262_264del | Homozygous | Autosomal, Recessive | Schepers et al. 1996 | 'Patient A' from the... | |
| 272750.2.1 | Saudi Arabia | Female | Yes | Yes | Pseudobulbar signs; Spastic tetraparesis... Pseudobulbar signs; Spastic tetraparesis; Limb dystonia; Abnormal pyramidal sign; Chorea; Glabellar reflex; Loss of ambulation; Expressive aphasia; Cerebral atrophy; Death in early adulthood | NM_000405.5:c.164C>T | Homozygous | Autosomal, Recessive | Salih et al. 2015 | 'Patient 1' in the p... |
| 272750.2.2 | Saudi Arabia | Female | Yes | Yes | Spastic tetraparesis; Limb dystonia; Cho... Spastic tetraparesis; Limb dystonia; Chorea; Glabellar reflex; Scoliosis; Brain atrophy; Mental deterioration; Hypokinesia | NM_000405.5:c.164C>T | Homozygous | Autosomal, Recessive | Salih et al. 2015 | Sister of 272750.2.1... |
| 272750.2.3 | Saudi Arabia | Male | Yes | Yes | Chorea; Brain atrophy; Dysarthria; Spast... Chorea; Brain atrophy; Dysarthria; Spastic gait; Dystonia; Expressive aphasia; Hypokinesia | NM_000405.5:c.164C>T | Homozygous | Autosomal, Recessive | Salih et al. 2015 | Cousin of 272750.2.1... |
| 272750.3.1 | Saudi Arabia | Male | No | Yes | Cognitive regression; Motor regression; ... Cognitive regression; Motor regression; Hallucinations; Orofacial dyskinesia; Facial tics | NM_000405.5:c.164C>T | Homozygous | Autosomal, Recessive | Maddirevula et al. 2020 |