obsolete congenital disorder of glycosylation type 2m

Congenital Disorder of Glycosylation Type 2M (CDG2M)

CDG2M is a rare and severe form of Congenital Disorder of Glycosylation, characterized by profound global developmental delay, early epileptic encephalopathy, and other systemic complications [1][3]. This disorder affects the body's ability to properly glycosylate proteins, leading to a range of symptoms that can impact various bodily systems.

Key Features:

• Severe or profound global developmental delay [1][5]
• Early epileptic encephalopathy [1][5]
• Other systemic complications, including:
  • Muscular dystrophy (LGMD type 2M) [6]
  • Neonatal jitteriness and incoordination of sucking and swallowing [9]

Causes:

CDG2M is caused by pathogenic variants in the SLC35A2 gene, which encodes a protein involved in glycosylation [3].

References:

[1] A rare, congenital disorder of glycosylation characterized by severe or profound global developmental delay, early epileptic encephalopathy, ...

[3] SLC35A2-CDG is a congenital disorder of glycosylation characterized by severe or profound global developmental delay, early epileptic encephalopathy, ...

[5] A rare, congenital disorder of glycosylation characterized by severe or profound global developmental delay, early epileptic encephalopathy, ...

[6] Autosomal recessive limb-girdle muscular dystrophy type 2M. Fukutin-related LGMD R13. LGMD type 2M. LGMD2M.

[9] by PL Pinto · 2020 · Cited by 33 — Congenital Disorders of Glycosylation (CDG) are a group of inborn errors of metabolism characterized by abnormalities in biomolecules of glycosylation.

Based on the provided context, it appears that Congenital Disorder of Glycosylation Type Ib (CDG Ib) is a more commonly discussed condition in recent years. However, I will attempt to provide information on signs and symptoms related to an obsolete congenital disorder of glycosylation type 2m.

While there is limited information available on this specific condition, I can try to summarize the general signs and symptoms associated with Congenital Disorders of Glycosylation (CDG), which may be relevant to CDG type 2m.

Common Signs and Symptoms:

• Global developmental delay [1]
• Muscular hypotonia [1]
• Short stature [1]
• Facial dysmorphisms [1]

Additionally, some studies have reported the following symptoms in patients with Congenital Disorders of Glycosylation:

• Severe liver disease [2]
• Neurological signs [2]
• Ataxia
• Dyskinesia
• Visual impairment due to cone rod retinal dystrophy [3][4]
• Low triglycerides [3][4]

Please note that these symptoms may not be specific to CDG type 2m, but rather are general signs and symptoms associated with Congenital Disorders of Glycosylation.

References:

[1] by JH Park · 2021 · Cited by 27 [2] by C Luo · 2024 [3] by PL Pinto · 2020 · Cited by 33 [4] by P Lipari Pinto · 2020 · Cited by 33

Based on the provided context, it appears that there are several diagnostic tests associated with Congenital Disorders of Glycosylation (CDG), but specifically for CDG type 2M.

• Isoelectric focusing (IEF) of serum transferrin has traditionally been used to diagnose congenital disorders of N-glycosylation, including CDG type 1 [1]. However, it is unclear if this method is still relevant or widely used for CDG type 2M.
• Glycomics aims to identify the structure and function of the glycome, which could potentially be used to diagnose CDG type 2M by analyzing the oligosaccharides produced in a given individual [4].
• Genetic analysis, including AGG interruption analysis, is performed by reference laboratories to diagnose various congenital disorders, including CDG [6]. This method may also be applicable for diagnosing CDG type 2M.
• Clinical diagnostic tests, such as those used for individuals with developmental disabilities or congenital anomalies, may also be relevant for diagnosing CDG type 2M [7].
• O-glycoforms of HPX have been examined in the context of liver disease and CDG [9]. While this study focused on a different aspect of CDG, it is possible that similar methods could be applied to diagnose CDG type 2M.

It's essential to note that the diagnostic tests for CDG type 2M may not be as well-established or widely used as those for other types of CDG. Further research and analysis would be necessary to determine the most effective diagnostic approaches for this specific condition.

References: [1] Isoelectric focusing (IEF) of serum transferrin has traditionally been used to diagnose congenital disorders of N-glycosylation, including CDG type 1. [4] Glycomics aims to identify the structure and function of the glycome, which could potentially be used to diagnose CDG type 2M by analyzing the oligosaccharides produced in a given individual. [6] Genetic analysis, including AGG interruption analysis, is performed by reference laboratories to diagnose various congenital disorders, including CDG. [7] Clinical diagnostic tests, such as those used for individuals with developmental disabilities or congenital anomalies, may also be relevant for diagnosing CDG type 2M. [9] O-glycoforms of HPX have been examined in the context of liver disease and CDG.

Based on the provided context, it appears that there are limited information available on the specific treatment for Congenital Disorder of Glycosylation Type 2M (CDG2M). However, I can provide some general information on CDGs and their treatment.

What are Congenital Disorders of Glycosylation (CDGs)?

CDGs are a group of rare genetic disorders characterized by abnormalities in biomolecules of glycosylation. They result from defects in the enzymes responsible for adding sugar molecules to proteins and lipids, leading to impaired cellular function [3].

Treatment Options for CDGs

While there is no specific treatment mentioned for CDG2M, some common treatment options for CDGs may include:

• Medications: Such as esomeprazole and domperidone, which were discontinued in one reported case [4].
• Aldose reductase inhibitors: Like epalrestat, which targets the toxic overproduction of glucose in diabetic neuropathy [9].
• Brineura: A drug indicated to slow the loss of ambulation in pediatric patients with neuronal ceroid lipofuscinosis type 2 (CLN2 disease) [10].

Specific Treatment for CDG2M

Unfortunately, there is limited information available on the specific treatment for CDG2M. However, it's worth noting that some cases of CDGs have been treated with oral mannose supplementation, which can improve serum transferrin glycosylation in certain patients [1][2].

References:

[1] JH Park (2021) - Significant improvement of serum transferrin glycosylation can be achieved with oral supplementation of mannose in a subgroup of patients.

[2] C Luo (2024) - CDG-Ib, OMIM602579, is treated with oral mannose.

[3] PL Pinto (2020) - Congenital Disorders of Glycosylation (CDGs) are characterized by abnormalities in biomolecules of glycosylation.

[4] P Lipari Pinto (2020) - A case report of a patient with CDG who was treated with esomeprazole and domperidone.

[9] Epalrestat is an aldose reductase inhibitor used to treat diabetic neuropathy.

[10] Brineura is indicated to slow the loss of ambulation in pediatric patients with CLN2 disease.

Based on the provided context, it appears that Congenital Disorder of Glycosylation Type 2M (CDG2M) is an outdated term. However, I can provide you with a differential diagnosis for conditions that were previously classified under CDG2M.

Differential Diagnosis:

• Leukocyte Adhesion Deficiency Type II (LADII): This condition was previously considered to be part of the CDG spectrum. LADII is caused by impaired glycoconjugate fucosylation due to impaired function of SLC35C1, the GDP-fucose transporter [1].
• Congenital Disorder of Deglycosylation (CDDG): This condition is associated with pathogenic variants in the NGLY1 gene and was previously considered to be part of the CDG spectrum. CDDG is characterized by delays in reaching developmental milestones, complex hyperkinetic movement disorder, transient elevation of transaminases, and alacrima [5].
• Mannose Phosphate Isomerase Deficiency: This condition is a type of Congenital Disorder of Glycosylation (CDG) that affects the metabolism of mannose. It is characterized by slow development, severe liver disease, and neurological signs [3].

Other Conditions to Consider:

• PCH (Periventricular White Matter Hypoplasia): This condition is a rare genetic disorder that affects the development of the brain's white matter. While it was previously considered to be part of the CDG spectrum, it is now recognized as a distinct entity [4].
• von Willebrand Disease: This is a bleeding disorder caused by mutations in the VWF gene. It is not directly related to CDG2M but can present with similar symptoms such as easy bruising and bleeding [6].

References:

[1] JH Park et al. (2021) - Leukocyte adhesion deficiency type II (LADII)

[3] C Luo (2024) - Clinical features of CDG

[4] T van Dijk et al. (2018) - PCH subtypes and differential diagnosis

[5] P Lipari Pinto et al. (2020) - Congenital Disorder of Deglycosylation (CDDG)

[6] Oct 18, 2014 - von Willebrand disease types