Ataxia, and Lymphopenia

Transcobalamin deficiency (TC) is a disorder of cobalamin transport that usually presents during the first few months of life and is characterized by megaloblastic anemia, failure to thrive, vomiting, weakness and pancytopenia.

TRANSCOBALAMIN DEFICIENCY Is also known as transcobalamin ii deficiency|inherited deficiency of transcobalamin|tc ii deficiency|tcn2 deficiency

• Intellectual disability
• Generalized hypotonia
• Ataxia
• Failure to thrive
• Muscle weakness

SOURCES: ORPHANET OMIM MENDELIAN

Congenital sideroblastic anemia -B cell immunodeficiency- periodic fever-developmental delay syndrome is a form of constitutional sideroblastic anemia (see this term), characterized by severe microcytic anemia, B-cell lymphopenia , panhypogammaglobulinemia and variable neurodegeneration. The disease presents in infancy with recurrent febrile illnesses, gastrointestinal disturbances, developmental delay, seizures, ataxia and sensorineural deafness. Most patients require regular blood transfusion, iron chelation, and intravenous immunoglobulin (IVIG) replacement. Stem cell transplantation has been reported to be successful.

CONGENITAL SIDEROBLASTIC ANEMIA-B-CELL IMMUNODEFICIENCY-PERIODIC FEVER-DEVELOPMENTAL DELAY SYNDROME Is also known as sifd syndrome

• Seizures
• Global developmental delay
• Generalized hypotonia
• Hearing impairment
• Ataxia

SOURCES: OMIM ORPHANET MENDELIAN

Purine nucleoside phosphorylase (PNP) deficiency is a disorder of purine metabolism characterized by progressive immunodeficiency leading to recurrent and opportunistic infections, autoimmunity and malignancy as well as neurologic manifestations.

PURINE NUCLEOSIDE PHOSPHORYLASE DEFICIENCY Is also known as pnp deficiency|pnpase deficiency|nucleoside phosphorylase deficiency

• Intellectual disability
• Generalized hypotonia
• Ataxia
• Failure to thrive
• Muscular hypotonia

SOURCES: ORPHANET OMIM MENDELIAN

Legionnaire disease (LD) is a type of pneumonia caused by Legionella pneumophila, a flagellated gram-negative bacterium found primarily in warm water environments. The disease and the bacterium were discovered following an outbreak traced to a 1976 American Legion convention in Philadelphia. A number of risk factors for acquiring LD have been identified, including age, smoking, chronic lung disease, cancer, and immunosuppression (summary by Hawn et al., 2003).

• Ataxia
• Neoplasm
• Muscle weakness
• Pain
• Peripheral neuropathy

SOURCES: ORPHANET OMIM MENDELIAN

Familial hemophagocytic lymphohistiocytosis-2 (FHL2) is an autosomal recessive disorder of immune dysregulation with onset in infancy or early childhood. It is characterized clinically by fever, edema, hepatosplenomegaly, and liver dysfunction. Neurologic impairment, seizures, and ataxia are frequent. Laboratory studies show pancytopenia, coagulation abnormalities, hypofibrinogenemia, and hypertriglyceridemia. There is increased production of cytokines, such as gamma-interferon (IFNG ) and TNF-alpha (OMIM ), by hyperactivation and proliferation of T cells and macrophages. Activity of cytotoxic T cells and NK cells is reduced, consistent with a defect in cellular cytotoxicity. Bone marrow, lymph nodes, spleen, and liver show features of hemophagocytosis. Chemotherapy and/or immunosuppressant therapy may result in symptomatic remission, but the disorder is fatal without bone marrow transplantation (summary by Dufourcq-Lagelouse et al., 1999, Stepp et al., 1999, and Molleran Lee et al., 2004).For a general phenotypic description and a discussion of genetic heterogeneity of FHL, see {267700}.

HEMOPHAGOCYTIC LYMPHOHISTIOCYTOSIS, FAMILIAL, 2; FHL2 Is also known as hplh2|hlh2

• Seizures
• Global developmental delay
• Generalized hypotonia
• Ataxia
• Failure to thrive

SOURCES: OMIM MENDELIAN

NPHS14 is an autosomal recessive syndromic form of steroid-resistant nephrotic syndrome with multisystemic manifestations. Most affected individuals present in infancy or early childhood with progressive renal dysfunction associated with focal segmental glomerulosclerosis (FSGS) and resulting in end-stage renal disease within a few years. Other infants present with primary adrenal insufficiency. Some patients present in utero with fetal hydrops and fetal demise. Additional features of the disorder can include ichthyosis, acanthosis, adrenal insufficiency, immunodeficiency, and neurologic defects (summary by Prasad et al., 2017 and Lovric et al., 2017).For a discussion of genetic heterogeneity of nephrotic syndrome and FSGS, see NPHS1 (OMIM ).

FAMILIAL STEROID-RESISTANT NEPHROTIC SYNDROME WITH ADRENAL INSUFFICIENCY Is also known as primary adrenal insufficiency-steroid-resistant nephrotic syndrome due to sgpl1 deficiency

• Seizures
• Global developmental delay
• Generalized hypotonia
• Hearing impairment
• Microcephaly

SOURCES: ORPHANET OMIM MENDELIAN

PGM3-CDG is a rare congenital disorder of glycosylation caused by mutations in the PGM3 gene and characterized by neonatal to childhood onset of recurrent bacterial and viral infections, inflammatory skin diseases, atopic dermatitis and atopic diatheses, and marked serum IgE elevation. Early neurologic impairment is evident including developmental delay, intellectual disability, ataxia, dysarthria, sensorineural hearing loss, myoclonus and seizures.

PGM3-CDG Is also known as cid due to pgm3 deficiency|immunodeficiency with hyper ige and cognitive impairment|pgm3-related congenital disorder of glycosylation|combined immunodeficiency due to pgm3 deficiency|immunodeficiency-vasculitis-myoclonus syndrome|ivms

• Intellectual disability
• Seizures
• Global developmental delay
• Short stature
• Generalized hypotonia

SOURCES: OMIM ORPHANET MENDELIAN

Ataxia-pancytopenia syndrome is a rare genetic disease characterized by cerebellar ataxia, cytopenias and predisposition to bone marrow failure and myeloid leukaemia. Neurologic features variably include slowly progressive cerebellar ataxia or balance impairment with cerebellar atrophy and periventricular white matter T2 hyperintensities in brain MRI, horizontal and vertical nystagmus, dysmetria, dysarthria, pyramidal tract signs and reduced nerve conduction velocity. Hematological abnormalities are variable and may be intermittent and include cytopenias of all cell lineages, immunodeficiency, myelodysplasia and acute myeloid leukemia.

ATAXIA-PANCYTOPENIA SYNDROME Is also known as myelocerebellar disorder

• Microcephaly
• Scoliosis
• Ataxia
• Nystagmus
• Anemia

SOURCES: MESH OMIM ORPHANET MENDELIAN

Neonatal glycine encephalopathy is a frequent, usually severe form of glycine encephalopathy (GE; see this term) characterized by coma, apnea, hypotonia, seizure and myoclonic jerks in the neonatal period, and subsequent developmental delay.

NEONATAL GLYCINE ENCEPHALOPATHY Is also known as classic glycine encephalopathy|neonatal nkh|nkh|neonatal non-ketotic hyperglycinemia|hyperglycinemia, nonketotic

• Intellectual disability
• Seizures
• Global developmental delay
• Generalized hypotonia
• Microcephaly

SOURCES: ORPHANET OMIM MENDELIAN

Dihyropyrimidine dehydrogenase deficiency shows large phenotypic variability, ranging from no symptoms to a convulsive disorder with motor and mental retardation in homozygous patients. In addition, homozygous and heterozygous mutation carriers can develop severe toxicity after the administration of the antineoplastic drug 5-fluorouracil (5FU), which is also catabolized by the DPYD enzyme. This is an example of a pharmacogenetic disorder (Van Kuilenburg et al., 1999).Since there is no correlation between genotype and phenotype in DPD deficiency, it appears that the deficiency is a necessary, but not sufficient, prerequisite for the development of clinical abnormalities (Van Kuilenburg et al., 1999; Enns et al., 2004).

DIHYDROPYRIMIDINE DEHYDROGENASE DEFICIENCY Is also known as pyrimidinemia, familial|familial pyrimidinemia|dpyd deficiency|dpd deficiency|thymine-uraciluria, hereditary

• Intellectual disability
• Seizures
• Global developmental delay
• Generalized hypotonia
• Microcephaly

SOURCES: MESH OMIM ORPHANET MENDELIAN